Responding to a challenge that tragic necessity has thrown to countless research labs around the world, a team from the Department of Chemistry will deploy its new cell mapping technology to shed light on the molecular interplay between COVID-19 and its host. The team is collaborating with Princeton molecular biologists who study viruses.

Fifty percent of production spending in Ireland is now animation.

The post Ireland’s Animation Industry Spending Has Overtaken Live-Action Film And TV Combined appeared first on Cartoon Brew.

The following summarize enforcement actions the U.S. Environmental Protection Agency’s Region 10 office completed in January and February of 2020. The concluding legal document(s) typically provide details of the case and are included at the end of each summary.

WASHINGTON (April 30, 2020) — The U.S.

It has been an unfortunate eternity since I was last at an available computer to tap out our latest adventures. Right now I am currently in Berlin and I have yet to even write of Belgium or our time in Amsterdam. So let me get to that right away.Au

The FAI have sought more clarity from Sport Ireland and the HSE as they look to nail down a return date for the game at all levels.

The special education courts are designed to protect the legal rights of those children, but the city’s system is so overburdened that vulnerable students wait months or years for help getting critical support, according to the legal complaint.

Quantum physics impacts the technology students use every day. Use these resources from NOVA broadcasts, NOVA Digital, and What the Physics!? to introduce quantum concepts to your classroom.

Blues defenseman Jay Bouwmeester went into cardiac arrest during a game against the Ducks on Tuesday. Ducks medical personnel helped save his life.

Mookie Betts wasn't too worried when he became ill at the end of last week. While the country was dealing with the growing COVID-19 outbreak, he was dealing with food poisoning.

Retailing for $2,070 and $3,150, respectively, the Philipp Plein tank top and hoodie are being sold to support the Mamba & Mambacita Sports Foundation, which was started by Lakers legend Kobe Bryant.

Hand sanitizer is not the only coronavirus necessity. Students stuck at home in close and noisy quarters could use headphones to keep out distractions and allow them to focus on their studies.

No Democratic candidates called for social distancing before Super Tuesday, and now the left is Monday-morning quarterbacking the president.

The five Oscar-nominated live-action shorts of 2020: 'Brotherhood,' 'Saria,' 'Nefta Football Club,' 'My Neighbors' Window,' 'A Sister.'

"The Neighbors' Window" starts as an exercise in vicarious living and ends up as an experience in experiencing lives together.

Television writer-producer Matt Olmstead and his wife, NBC Universal executive Dawn Parouse Olmstead, sell a home in Newport Beach for $3.2 million.

'We absolutely reject the fact that firms should be denying their obligations under these rules,' said Abta chief executive Mark Tanzer

Netflix's animated adaptation of Lois Lowry's book "The Willoughbys," featuring the voices of Will Forte, Maya Rudolph and Martin Short, is hard to love.

In Netflix's "Extraction," an ambitious mix of action and emotion directed by Sam Hargrave, Chris Hemsworth stars as a moody mercenary.

Chris Hemsworth and the team behind the new Netflix action movie "Extraction" on releasing the film into a world unrecognizable from when they made it.

The makers of Netflix's "Extraction" explain the ambiguous ending and sequel plans for the Chris Hemsworth action film.

Storm Ciara is threatening to cause chaos with this week's sporting events including Premier League football, Six Nations rugby and eight horse racing meets.

Many are afraid that tackling climate change is going to be too costly. But increasingly, studies are showing action will not just be cheaper than inaction, but could actually result in economic, environmental and even health benefits, while improving sustainability.

This new page includes more information on the above issues.

Read full article: Action on climate change is cheaper than inaction

POLICE in Essex have admitted the decision was made to "take no further action" on many low level traffic offences last month as road crimes hit record levels.

THE summer that just keeps giving had the swallows all in a flutter last week. On the south coast of the Isle of Wight hundreds streamed past me and my family as we walked over the downs, enchanted by dart-like birds racing over the white cliffs and the green sward. Yet they were flying north-east instead of south towards Africa. Some were even coming in from the sea instead of heading out over the Channel.

Memories of our most beloved amusements

A man was killed on Indy's northwest side after what IMPD reported was an exchange of gunfire with an officer.

As IndyCar's iRacing Challenge ventures onto an oval track, expect the rhythm of the competition and, perhaps, those winning, to change.

Gov. Mike Pence's Scott County order allowing a needle-exchange program is a welcome step. But it's just a start.

Donnie Strack, now in the Thunder front office, checked out Utah's Rudy Gobert on the night of the league's first COVID-19-related cancellation.

Watch highlights from the crash-filled second race of the Formula E Race At Home Challenge as Maximillian Gunther wins on the Electric Docks circuit.

Goff is using play-action more often than any other quarterback in 2018.

The option of cryptocurrencies or electronic currencies for websites is increasingly stronger as a mechanism for the purchase of products and services, not only on the Internet but also in some businesses that have begun to accept this means of payment. If you’re working on a crypto-related project or a client who accepts cryptocurrency payments, […]

The post Tools You Should Know To Protect Bitcoin Transactions appeared first on SpyreStudios.

Instant Reaction: September Jobs Report

Instant reaction: NAR’s Lawrence Yun on Case-Shiller

As some of you may have noticed, last100 has been dormant of late and even off-line for a few weeks. The truth is that other blogging and work commitments have kept me very busy recently but more serious, the site was hacked. Badly. Malware was installed through a back door exploit and I had to [...]

Instant Reaction: Unemployment, May 8, 2020

It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience.

—Albert Einstein, “On the Method of Theoretical Physics” (1934)

Context: Last week, I pinched off one of my typically woolly emails in response to an acquaintance whom I admire. He’s a swell guy who makes things I love, and he'd written, in part, to express concern that my recent Swift impersonation had been directed explicitly at something he'd made. Which, of course, it hadn’t—but which, as I'll try to discuss here, strikes me as irrelevant.

To paraphrase Bogie, I played it for him, so now I suppose I might as well play it for you.

(n.b.: Excerpted, redacted, munged, and heavily expanded from my original email)

There are at least a couple things that mean a lot to me that I'm still just not very good at.

• Make nuanced points in whatever way they need to be made; even if that ends up seeming “un-nuanced”
• Never explain yourself.

I want to break both these self-imposed rules privately with you here. [Editor’s Note: Um.] Because, I hope to nuance the shit out of some fairly un-nuanced points. And, to do that, I'll also (reluctantly) need to explain myself. But, here goes.

First [regarding my goofing on “distraction-free writing environments”] I think there are some GIANT distinctions at play here that a lot of folks may not find nearly as obvious as I do:

1. Tool Mastery vs. Productivity Pr0n – Finding and learning the right tools for your work vs solely dicking around with the options for those tools is just so important, but also so different. And, admittedly, it’s almost impossible to contrast those differences in terms of hard & fast rules that could be true for all people in all situations. But, that doesn’t make the difference any less qualitatively special or real.
   
   Similarly…

2. Self-Help Vs. “Self”–“Help” – Solving the problem that caused the problem that caused the problem that caused the symptom we eventually noticed. Huge. Arguably, peerless.

   • Viz.: How many of us ignore the actual cause of our problem in favor of just reading dozens of blog posts about how to “turbocharge” its most superficial symptoms? Sick.

3. Focus & Play – Yes, focusing on important work is, as Ford used to say, Job 1. But, that focus benefits when we maintain the durable and unapologetic sense of play that affords true creativity and fosters an emergence of context and connection that’s usually killed by stress. BUT.

   • Again, what conceivable “rule” could ever serve to immutably declare that “THIS goofing-off is critical for hippocampal plasticity” vs. “THAT goofing-off is just dumb, distracting bullshit?”

   • Impossible. Because drawing those kinds of distinctions is one of our most important day-to-day responsibilities. Decisions are hard, and there’s no app or alarm gadget that can change that.

     • Although, they certainly can help mask the depth of the underlying problem that made them seem so—what’s the parlance?—“indispensable”.
     • Think: Elmo Band-Aids for that unsightly pancreatic tumor.

4. Reducing Distraction through Care (Rather than braces, armatures, and puppet strings). Removing interruptions and external distractions that harm your work or life? Great. Counting on your distraction-removal tool to supplement your non-existent motivation to do work that will never get done anyway? Pathetic.

   • Frankly, this is a big reason I'm so galled when anyone touts their tool/product/service as being the poor, misunderstood artist’s new miracle medicine—rather than just admitting they've made a slightly different spoon.
   • Because, let’s be honest: although most of us have plenty of perfectly serviceable spoons, everybody knows collecting cutlery is way more fun than using it to swallow yucky medicine.

5. Using a System Vs. Becoming a System. Having a system or process for getting work done vs. making the iteration of that system or process a replacement for the work. This is just…wow…big.
   
   But, maybe most importantly to me…

6. Embracing the Impossibles. Getting past these or any other intellectual koans by simply accepting life’s innumerable and unresolvable paradoxes, hypocrisies, and impossibilities as God-given gifts of creative constraint. Rather than, say, a mimeographed page of long division problems that must be solved for a whole number, n.

   • I just can’t ever get away from this one. For me, it’s what everything inevitably comes back to.
   • The very definition of our jobs is to solve the right problem at the right level for the right reason—based on a combination of the best info we have for now and a clear-eyed dedication to never pushing an unnecessary rock up an avoidable hill.

   • YET, we keep force-feeding the monster that tells us to fiddle and fart and blame the Big Cruel World whenever we face work that might threaten our fragile personal mythology.

     • “Sigh. I wish I could finally start writing My Novel….Ooooooh, if only I had a slightly nicer pen…and Zeus loved me more….”

All that stuff? That there’s a complex set of ideas to talk about for many complex reasons—not least of which being how many people either despise or (try to) deny the unavoidable impact of ol' number six.

But, here’s the thing: as much as saying so pisses anybody off, I think the topics we're NOT talking about whenever we disappear into Talmudic scholarship about “full-screen mode” or “minimalist desks” or whatever constitutes a “zen habit”—those shunned topics are precisely the things that I believe are most mind-blowingly critical to our real-world happiness as humans.

In fact, I believe that to such a degree that helping provide a voice for those unpopular topics that can be heard over the din is now (what passes for) my career. I really believe these deeper ideas are worth socializing on any number of levels and in many media. Even when it’s inconvenient and slightly disrespectful of someone’s business model.

So, that’s what I try to do. I talk about these things. Seldom by careful design. Often poorly. But, always because they each mean an awful lot to me.

[…]

But, no matter how I end up saying whatever the hell I say, I believe in saying it not simply to be liked or followed or revered as a “nice guy” who pushes out shit-tons of whatever to “help people.”

Because, believe me, friend, a great many of those apparently “nice guys” swarming around the web “helping people” these days are ass-fucking their audience for nickels and calling it a complimentary colonoscopy. And, while I absolutely think that in itself is empirically wrong, I also think it’s just as important to say that it’s wrong. Sometimes, True Things need to be said.

Which in this instance amounts to saying, a) selling people a prettier way to kinda almost but not really write is not, in the canonical sense, “nice”—but, far worse, b) leaving your starry-eyed customers with the nauseatingly misguided impression that their “distraction” originates from anyplace but their own busted-ass brain is really not “helping.” Not on any level. It is, literally, harmful.

“Helping” a junkie become more efficient at keeping his syringe loaded is hardly “nice.”

It’s the opposite of nice. And, it’s the opposite of helpful. These are my True Things.

And, to me, saying your True Things also means not watering down the message you care about in order to render it incapable of even conceivably hurting someone’s feelings—or of even conceivably losing you even one teeny-tiny slice of that precious “market share.”

Well, that’s the price, and I'm fine paying it—best money I've ever spent.

But, it also means trusting your audience by letting each of them decide to add water only as they choose to—by never corrupting the actual concentrate in a way that might make it less useful to the smartest or most eager 5% of people who'd like to try using it undiluted. Because, at that point, you're not only abandoning the coolest people you have the honor of serving—you risk becoming a charlatan.

And, that’s precisely what you become when you start to iteratively inbreed the kind of fucktard audience for whom daily buffets of weak swill and beige assurance are life’s most gratifying reward.

Sure. Those poor bastards may never end up using any of that watery information to do anything more ambitious than turbocharging their most regrettable symptoms. But, who’s the last person in the universe who’s going to grab them by the ears and tell them to get back to work? Exactly—that same “nice guy” whose livelihood now depends on keeping infantalized strangers addicted to his “help.”

Holy shit—no way could I ever live with that. It’s so wrong, it’s not even right. ESC, ESC, ESC!

[…]

Okay. So anyhow, there’s a really long-winded, overly generous, and extremely pompous way of trying to say I don’t know how to do what I do except how I do it. But, I do genuinely feel awful when innocent people feel they have been publicly humiliated or berated simply because I'm some dick who hates people.

Which has to be my favorite irony of all.

When I was a kid, I thought my Mom was “mean” not to let me play in traffic on busy Galbraith Road. Today, I'm not simply grateful that she had the strength and resolve to be so “mean”—I actually can’t imagine how sad it would be to not have people in your life who care enough about your long-term welfare to tell you to stop fucking around in traffic. To where you eventually might start even seeking 12x-daily safety hacks from some of the very same drivers whose recklessness may eventually kill you. Wow.

[…]

Admitting when life is complicated or things aren’t shiny and happy all the time strikes me as a wonderfully sane and adult way to conduct one’s life. That there are so many folks offended by even the existence of this anarchic idea is not a problem I can solve.

No more than I can wish useless email away or pray hard enough that it never rains on anyone’s leaky roof. All out of scope.

And, then, I jizzed on at length about how much I admire the recipient’s work. Which I do.

Good work doesn’t need a cookie

I may admire your work, too. Especially if you care a lot about that work and don’t overly sweat peoples' opinions of it. Most definitely including my own.

For these purposes, it doesn’t really matter whether we're friends and, honestly, it doesn’t even matter whether I love, use, or agree with everything you do, say, or make in a given day.

It doesn’t matter because good work doesn’t need me to love it. Like tornadoes and cold sores, good work happens with total disregard to whether I'm “into it.”

But, conversely, let’s stipulate that the points-of-view undergirding our opinions—again, including mine—will and should survive either agreement or lack of agreement with equivalently effortless ease. Because, like really good work, a really good point-of-view doesn’t require another person’s benediction.

Guess we'll have to disagree to agree

Now, to be only vaguely clearer here, I'm not posting this circuitous ego dump in the service of altering your opinion of either me, my friend, his work, or practically anything else for that matter.

But, I would love it if we could all be more okay with the fact that real life means that we do each have a different, sometimes incongruous, and often totally incompatible point-of-view. Yes. Even you have a point-of-view that someone despises. Ready to change it now? Jesus, I sure hope not.

Then, to be only slightly more clear, I'm also not advocating for that fakey brand of web-based kum ba ya that gets trotted out alternately as “tolerance” or “inclusion” or some styrofoam miniature of “civility.”

I'm absolutely not against all of those things when authentically practiced, but I'm also really skeptical of the well-branded peacemakers who are forever appointing themselves the Internet’s “Now-Now-Let’s-All-Pretend-We're-Just-Saying-the-Same-Useless-Thing-Here” den mothers.

Because we're not all saying the same things. Not at all.

And, it infantalizes some important conversations when we tacitly demand that any instance of honest disagreement be immediately horseshat into a photo opp where some thought leader gets to hoist everyone’s hands in the air like he’s fucking Jimmy Carter.

Nope. Not saying that.

Who will you really rely on?

What I AM saying is that alllllll this seemingly unrelated stuff is absolutely related—that the pattern of not relying on other people for anything you really care about is arguably the great-grandaddy of every useful productivity, creativity, or self-help pattern.

Where’s this matter? Pretty much everywhere you have any sort of stake:

• Don’t rely on other people to remove your totally fake “distractions.”
• Don’t rely on other people to pat your beret, re-tie your cravat, and make you a nice cocoa whenever that mean man on the internet points out that your “distractions” are totally fake. (Which they are)
• Don’t rely on other people to tell you when or whether you have enough information.
• Don’t rely on other people to define your job.
• Don’t rely on other people to “design your lifestyle.”
• Don’t rely on other people to decide when your opinions are acceptable.
• Don’t rely on other people to tell you when you're allowed to be awesome.
• Don’t rely on other people to make you care.
• Don’t even rely on other people to tell you what you should or shouldn’t rely on.

Yes. I went there.

Because that’s the point. These hypocrisies, paradoxes, and ambiguities that people get so wound up about—that many of us are constantly (impotently) trying to resolve—cannot be resolved.

Because, yeah: all of these harrowingly unsolvable problems are immune to new notebooks and less-distracting applications and shinier systems and “nicer” self-“help” and pretty much anything else that is not, specifically, you walking straight into the angriest and least convenient shitstorm you can find and getting your ass kicked until the storm gets bored with kicking it.

Then, you find an even angrier storm. Then, another. And, so on.

“Get the fuck off of my obstacle, Private Pyle!”

Doing that annoying hard stuff is how you grow, get better, and learn what real help looks like. Even if that’s not the answer you wanted to hear. You get better by getting your ass out of your RSS reader and fucking making things until they suck less. Not by buying apps.

You don’t whine about distractions, or derail yourself over needing a nicer pencil sharpener, or aggravate your chronic creative diabetes by starting another desperate waddle to the self-help buffet. No. You work.

And, for what it’s worth, just like you can’t get to the moon by eating cheese, you'll also never leave boot camp with your original scrote intact by telling your drill sergeant to try using more honey than vinegar.

No. That sergeant’s job is to make you miserable. It’s his job to break down your callow conceits about what’s supposed to be easy and fair. It’s his job to emotionally pummel you into giving up and becoming a Marine.

You? You're not there to give the sergeant notes; you're there to sleep two hours a night, then not mind getting beaten for 20 hours until a decent Marine starts to fall out.

Who knows? He may even surprise you by introducing a surprisingly effective “distraction-free learning environment.”

“Tee ell dee ahr, Professor Brainiac.”

Like most humans, I like things I can understand. Like most readers, I love specificity. Like most thinkers, I love clarity. Like most students, I love relevance and practicality. And, like most busy people, believe it or not, I actually do really like it when someone gets straight to the point.

But, here’s the problem. If my 2-year-old daughter asks me about time travel, and I blithely announce, “E=mc²”, I will have said something that is entirely specific, clear, relevant, practical, and/or straight-to-the-point. For somebody.

But, not so much for my daughter. And, to be honest, not even to any useful degree for me.

She'd probably either laugh derisively at me (which she’s great at), or she'd pause and ask, “Whuh dat?” (which she’s even better at).

Thing is, her understanding that jumble of characters less than me—and my understanding it WAY less than Professor Al—has zero impact on the profundity, truth, beauty, or impact of the man’s theory.

Sure. You could quite accurately fault me for being a smartass and a poseur, and you could even berate my toddler for her unaccountably shallow understanding of Modern Physics. But, in any case, you can’t really blame either Albert or his theory.

You're turbocharging nothing

Specifically, Albert can’t begin to tell us what he really knows if we don’t understand math.

So, let’s say this theory you've been hearing about really interests you. And, let’s also pretend, just for the sake of the analogy, that you haven’t completed Calculus III (212) or Quantum Mechanics (403) or even something as elementary as, say, Advanced Astrophysics II (537). I know you have. Obviously. But, let’s pretend. Where do you start?

Well, you could read some tips about learning math. You could find a list of 500 indispensable resources for indispensable math resources. You could buy a new “distraction-free math environment.” Heck, there’s actually nothing to stop you from just declaring yourself a “math expert.” Congratulations, Professor.

Thing is: you still don’t know math.

Which means you still can’t really understand the theory—no more than a pathetic Liberal Arts refugee like me or a dullard Physics ignoramus like my kid can really grok relativity.

Difference is, you will have blown a lot of time hoping that actual expertise follows non-existent effort—while my daughter and I get to remain total novices without charge. Only, we don’t get all mad at the theory as a result; a staggering number of fake math experts do.

I mean, be honest—after all that recreational non-work and make-believe dedication almost trying to kinda learn math sorta—you might actually get frustrated at how brazenly Al defies your fondness for shortcuts by continuing to rely on so many terms and proofs and blah-blah-blah that you still just don’t understand. So annoying.

You may simply decide that Albert Einstein’s a huge dick for never saying things that can be completely understood solely by scanning a headline.

EPIC EINSTEIN FAIL, amirite?

You never really know what you didn’t know until you know it

But, Al just told the truth.

Problem is, Al’s truth not only requires fancy things in order to be truly understood—the more of those fancy things you take away from his truth, the less true it gets. And, by the time it’s been diluted to the point where you're comfortable that you understand it? You'd be understanding the wrong thing. Even I can understand that.

But, not one bit of any of this is Al’s fault. Al doesn’t get to control who uses, abuses, gets, or doesn’t get what he said or why it matters. Especially since he’s been dead for over fifty years.

All I know is, regardless of who has ears to hear it on a given day, it would be to Al’s credit never to mangle something important in order to get it into terms everybody’s ready to handle without actually trying.

And God bless him for never agreeing that your “distractions” to learning math are his problem.

So, yeah, if you only need to hand in a crappy 5-page paper, you could certainly Cliff’s Notes your way through Borges, Eliot, or Joyce in an afternoon, and feel like you haven’t missed a thing. Trouble is, if you did care even a little, it’s impossible to even say how much you're missing since you can’t be bothered to soldier through the source text. The text itself is the entire point.

Even the wonderfully cogent and readable layman’s explanations Einstein himself provided don’t really get to the nut, the application, and the implications of his real theory.

That all takes real math.

That “single datum of experience” matters

Sometimes, complex or difficult things stop being true when you try to make them too simple. Sometimes, you have to actually get laid to understand why people think sex is such a thing. Sometimes, you need to learn some Greek if you really want to understand The Gospel of John. And, yeah, sometimes, you're going to have to just work unbelievably hard at whatever you claim to care about before anyone can begin to help you get any better—or less “distracted”—at it.

The part I really know is what doesn’t work. Reading Penthouse Forum won’t help you CLEP out of Vaginal Intercourse 101. Watching a Rankin-Bass cartoon about the Easter Bunny will teach you very little about the intricacies of transubstantiation. And, if you can’t be troubled to care so much about your work that you reflexively force distractions away, dicking around with yet another writing application will merely aggravate the problem. Ironic, huh?

These quantum mechanics of personal productivity are rife with such frustrating “paradoxes.”

These are True Things.

Achieving expertise and doing creative work is all horribly complicated and difficult and paradoxical and frustrating and recursive and James Joyce-y—and any guide, blog, binary, guru, or “nice guy” that tries to suggest otherwise is probably giving you a complimentary colonoscopy. Do the math.

Want a new syllabus? Sure:

Run straight into your shitstorm, my friends. Reject the impulse to think about work, rather than finishing it. And, open your heart to the remote possibility that any mythology of personal failure that involves messiahs periodically arriving to make everything “easy” for you might not really be helping your work or your mental health or your long-standing addiction to using tools solely to ship new excuses.

Learn your real math, and any slide rule will suffice. Try, make, and do until you quit noticing the tools, and if you still think you need new tools, go try, make, and do more.

If you can pull off this deceptively simple and millennia-old pattern, you'll eventually find that—god by dying god—any partial truth that’s supported your treasured excuses for not working will be replaced by a no-faith-required knowledge that you're really, actually, finally getting better at something you care about.

Which is just sublimely un-distracting.

Dedication

This article is dedicated to my friend, Greg Knauss. No, he’s not the app guy–he’s just a good man who does good work, who accidentally/unintentionally helped me write this rant. He also happens to be a fella who could teach anyone a thing or two about writing with distractions. Thanks, Greg.

Open Letter by the conveners of the Vision Europe Summit regarding the refugee crisis in Europe and the necessity to act now.

Invitation Only Research Event

Event participants

Xenia Wickett, Project Director, US; Dean, The Queen Elizabeth II Academy for Leadership in International Affairs, Chatham House
Dr Christian Moelling, International Security Division Associate, SWP-Berlin

15 April 2020

Marilyn Goudreault
Jan 1, 2009; 8:157-171
Research

Amelia C. Peterson
Nov 1, 2012; 11:1475-1488
Technological Innovation and Resources

Ludovic C. Gillet
Jun 1, 2012; 11:O111.016717-O111.016717
Research

Leigh Anderson
Apr 1, 2006; 5:573-588
Research

Jürgen Cox
Sep 1, 2014; 13:2513-2526
Technological Innovation and Resources

In our computational study, we use molecular simulations to substantiate a hypothetical mechanism for glycosidic bond cleavage in the presence of a single catalytic acid at the active site of the mutant D10N HiCel45A. In addition to discussing this plausible mechanism from the context of structurally related MltA lytic transglycosylase and subfamily C GH45s, we also suggest the implications of the plausible mechanism for our current understanding of the action of expansins and lytic transglycosylases. As correctly pointed out by Professor Cosgrove (1), there is large body of evidence, a significant portion of which was regrettably not discussed in our paper, that suggests that expansins are incapable of lytic action on polysaccharide substrates. Whereas these insights do not change the results or the conclusions of our article, we would like to thank Professor Cosgrove for these additional insights. In particular, our main point with respect to expansins is that our results suggest the possibility that expansins are capable of nonhydrolytic lytic activity. Our intention was not to suggest this was the mechanism of expansins, but that it should be considered based on our results and the similarity of the active sites.The molecular mechanisms of how expansins enable cell wall expansion remains to be fully understood. Whereas our proposed mechanism resulting in the formation of the 1,6-anhdro product might be found in expansins and might contribute to the mode of action of expansins, we would like to emphasize that the intent of this study was only to suggest this as a...

From their simulations of endoglucanase Cel45A, Bharadwaj et al. (1) propose that structurally related expansins and MltA may cut glycan backbones without generating reducing ends. This is tenable for MltA, a peptidoglycan lytic transglycosylase whose action produces nonreducing 1,6-anhydro products, but is untenable for expansins.Expansins loosen plant cell walls and induce wall expansion. Contrary to the assertion by Bharadwaj et al., the conclusion that expansins are not lytic is not merely based on lack of new reducing ends but is supported by multiple (negative) tests for polysaccharide cleavage that do not rely on detection of reducing ends. At least eight studies with three divergent groups of expansins document this point. For instance, α-expansin did not reduce the viscosity of various wall polysaccharide solutions, an endolytic assay that does not rely on measuring reducing ends (e.g. see Ref. 2 and other studies).Walls treated with α-expansin did not release saccharide fragments, measured by pulsed amperometric detection, which can detect nonreducing saccharides (3).In the case of β-expansins, protein treatments did not cleave the backbones of a wide range of dye-coupled cross-linked wall polysaccharides; nor did they cleave backbones of polysaccharides extracted from plant cell walls, measured by gel permeation chromatography (4).For five microbial expansins, tests with a range of dye-coupled cross-linked polysaccharides likewise did not detect lytic activity (e.g. see Ref. 5). Thus, extensive published evidence argues against lytic action by expansins, as proposed by Bharadwaj (1), and attempts to identify 1,6-anhydro products seem unlikely to succeed.

The quinoprotein glycine oxidase from the marine bacterium Pseudoalteromonas luteoviolacea (PlGoxA) uses a protein-derived cysteine tryptophylquinone (CTQ) cofactor to catalyze conversion of glycine to glyoxylate and ammonia. This homotetrameric enzyme exhibits strong cooperativity toward glycine binding. It is a good model for studying enzyme kinetics and cooperativity, specifically for being able to separate those aspects of protein function through directed mutagenesis. Variant proteins were generated with mutations in four active-site residues, Phe-316, His-583, Tyr-766, and His-767. Structures for glycine-soaked crystals were obtained for each. Different mutations had differential effects on kcat and K0.5 for catalysis, K0.5 for substrate binding, and the Hill coefficients describing the steady-state kinetics or substrate binding. Phe-316 and Tyr-766 variants retained catalytic activity, albeit with altered kinetics and cooperativity. Substitutions of His-583 revealed that it is essential for glycine binding, and the structure of H583C PlGoxA had no active-site glycine present in glycine-soaked crystals. The structure of H767A PlGoxA revealed a previously undetected reaction intermediate, a carbinolamine product-reduced CTQ adduct, and exhibited only negligible activity. The results of these experiments, as well as those with the native enzyme and previous variants, enabled construction of a detailed mechanism for the reductive half-reaction of glycine oxidation. This proposed mechanism includes three discrete reaction intermediates that are covalently bound to CTQ during the reaction, two of which have now been structurally characterized by X-ray crystallography.

Vitali Matyash
May 1, 2008; 49:1137-1146
Methods