Nature, Science, & Mathematics: September 2009 Archives

Interesting Insights Along the Way


The following entry was originally posted by Paul Draper on his facebook site. I think the thought, while perhaps a bit simplified, is a starting point for an excursus into the understanding of the interface of science and religion.

The Marvelous Tale of Chaperonin, the Patron Saint of Useless Proteins
Paul Draper

September 9, 2009 at 1:08pm

I know next to nothing about biology, and I yesterday I heard the most amazing thing, mentioned almost in passing. I was struck dumb by it, but I get the feeling that if I said, "Wait a sec, that's extraordinary!" a biologist would say, "Oh, yeah, crazy s&$# like that happens all over the place in biology." And I'm going to try to explain this in the way I understand it, not the way a biologist would understand it, because... well, I'm not a biologist.

Proteins are made of long chains of amino acids, which are little T-shaped molecules, and where the left tip of the cross-bar of the T of one molecule connects with the right tip of the cross-bar of the T in the next molecule, leaving all those vertical legs sticking out of the side of the chain. There are 20 different kinds of those vertical legs, and they all have different chemical widgets at the ends. Some have the chemical equivalent of velcro side A, some velcro side B, some hooks, some eyes, some magnetic north poles, some magnetic south poles, some little oily bits that recoil from water, and so on.

And what happens is that this long chain tends to kink and twist and fold up, controlled completely by the velcro side A on one amino acid finding the velcro side B on another, the hook on one finding the eye on another, and so on. You get phone-cord spirals and bobby-pin bends and loom-shuttle sheets first, and then it tangles up some more. The thing is, how it tangles up, and the final shape of the tangled up mess is EVERYTHING to how the protein works. It's got to have that pocket lined with strips of velcro, or that knob with magnet poles, to be the enzyme it's supposed to be or the cell membrane ion channel it's supposed to be. If it doesn't fold up to that shape, then it's useless, and the key is that what shape it will tangle into is completely controlled by that sequence of T's with different widgets.

Now, you can imagine how evolution plays here. Sequences that fold up into a shape that isn't useful will be eventually culled, and sequences that fold into a shape that do something useful will be kept. So there's a natural mechanism for sorting out what in the end gets made and doesn't get made. Evolution is a heartless taskmaster, and proteins that don't do anything worthwhile get the pink slip.

But wait! There's a very complex protein called chaperonin, and it is another thing that folds up to serve a specific purpose. It looks like a snake-charmer's basket, complete with a lid. And what it does is this: It opens its lid and accepts an amino acid chain AND HELPS THAT CHAIN FOLD ITSELF CORRECTLY TO BE USEFUL. That is, it takes a protein that, on its own, would fold itself into something that is useless, and it helps it instead fold itself into something that is useful.

The question at the heart of this is: who ordered the chaperonin?

How does evolution, the heartless taskmaster, look at a useless protein and figure out that maybe there's inner value to that protein, if only there were a guardian angel that could help it do what it can't do on its own? What evolutionary happenstance created the patron saint protein whose sole purpose is to elevate more humble proteins to useful purpose?

This is the kind of thing that, the more you look at it, the more you marvel at how beautiful it is. There is soul in even the coldest machine, if you walk slowly enough to notice it. That's the way I see it, anyway.

Below is my original response to Paul:

Beautifully said, nicely explained. And only one of many things that argues against strict exaptation or even strict empiricism. When we come to a point like this, we enter into the realm of the philosophical subtext of science and we are no longer on the ground of what can be proven--merely what can be observed. Thank you for the note.

I would add to it that while some of the details may not be exactly on target, I think the overall discussion accurate for a layperson and insightful.

I don't think the conclusion is ultimately "intelligent design." But rather that God is imprinted on all of creation--without exception. In this way, I am far closer to Francis S. Collins than Michael Behe. But now we've gotten to the unstated philosophy that underlies any given theory. And philosophy, of itself is not subject to the rigors of the scientific method--such a method is incompatible with the means and ends of most philosophical investigation and most objects that philosophy purposes to examine. That is to say, the observations and explanations of the natural world are certainly subject to the rigors that science brings---however, the underlying whys may not always be amenable to the methods of science.

Bookmark and Share



About this Archive

This page is a archive of entries in the Nature, Science, & Mathematics category from September 2009.

Nature, Science, & Mathematics: February 2009 is the previous archive.

Find recent content on the main index or look in the archives to find all content.

My Blogroll