Evolution cheats, or how to get an old enzyme to do new tricks

Posted 1 August 2011 by Steve Matheson

It is of course a cliche to state that eukaryotic cells (i.e., cells that are not bacteria) are complex. In the case of an animal, tens of thousands of proteins engage in fantastically elaborate interactions that somehow coax a single cell into generating a unique and magnificent organism. These interactions are often protrayed as exquisitely precise, using metaphorical images such as 'lock-and-key' and employing diagrams that resemble subway maps. Many of these interacting proteins are enzymes that modify other proteins, and many of those enzymes are of a particular type called kinases. Kinases do just one thing: they attach phosphate groups to other molecules. This kind of modification is centrally important in cell biology, and one way to tell is to look at how many kinases there are: the human genome contains about 500 kinase genes. Now, kinases tend to be pretty picky about who they stick phosphate onto, and this specificity is known to involve the business end of the kinase, called the active site. The active site is (generally) the part of the kinase that physically interacts with the target and transfers the phosphate. You might think that this interaction, between kinase and target, through the active site, would be by far the most important factor in determining the specificity of kinase function. But that's probably not the case.

10 Comments

DS · 1 August 2011

But it's still a kinase!

Well, somebody had to say it.

Rumraket · 2 August 2011

Que some Axe/Dembski-ish apologist with the argument from giant numbers and "stable protein folds" having a rarity of about 1 in 10^77 or something thereabouts(which, according to the Disinformation Institute, Axe has proved). Further enhanced by the claim that "there are no functional intermediates" so the target protein can't be reached by "a random walk" in sequence space. Well, that's their usual response.

Atheistoclast · 2 August 2011

This comment has been moved to The Bathroom Wall.

DS · 2 August 2011

Atheistoclast said: In the case of an animal, tens of thousands of proteins engage in fantastically elaborate interactions that somehow coax a single cell into generating a unique and magnificent organism. No. Proteins do not conspire to build whales any more than bricks and mortar self-assemble into buildings. Ontogeny is not merely the outcome of protein-protein interactions.

I know I'm convinced. Thanks so much for answering all of my questions and explaining your alternative hypothesis in detail. Now I am a true believer. Look dude, here is a clear example of a protein taking on a new function. Something you claimed was impossible. You were wrong , just admit it. Still waitin for an explanation of those SINE insertions. You know, that information you say cannot exist.

Atheistoclast · 2 August 2011

This comment has been moved to The Bathroom Wall.

Steve Matheson · 2 August 2011

Atheistoclast said: Have you read the PNAS paper: http://www.pnas.org/content/108/24/9809.full Or are you just going on what SteveM reports? I am reading it when I have time. Enzymes do not acquire new functions. They can be modified to an extent, with altered reactive properties, but always remain variations on the same biochemical theme.

'Clast, as long as your comments consist of blatant assertions seemingly designed as flamebait, they will be discussed on the Bathroom Wall. Both of your comments so far on this thread are examples of blatant assertion, and your first comment is demonstrably false. When you are ready to contribute informed dissent, or whenever you wish to express skepticism regarding scientific conclusions of any kind, you'll be welcome on the normal comment pages. From now on, however, the default for your comments is the Bathroom Wall.

harold · 2 August 2011

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Atheistoclast · 3 August 2011

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The Jumbuck · 4 August 2011

This proves intelligent design and falsifies Darwinism. The fact the enzyme required a new functions implies foresight. This is something only an intelligent designer can have.

bigdakine · 4 August 2011

The Jumbuck said: This proves intelligent design and falsifies Darwinism. The fact the enzyme required a new functions implies foresight. This is something only an intelligent designer can have.

Look, if your gonna troll, please do a better job.