surface burial in energy calc's

David G. Rhodes rhodes at MODEL.PHR.UTEXAS.EDU
Fri Sep 23 15:49:48 EST 1994


On Sep 19,  4:08pm, Scott Le Grand wrote:
> Subject: Re: surface burial in energy calc's
.....
> Overall, it probably helps to keep you near the native structure if
> you start there, but if you attempt to perform a conformational
> search starting from randomness, I think you're doomed...
>                                                ^^^^^^^^^
>-- End of excerpt from Scott Le Grand

In 1921, G. Poyla showed that the probability that a random walk will
result in a return to the origin is 1 in one dimension, 1 in two
dimensions, and <1 in three dimensions.  As reported by Adam and Delbruck,
the actual number is 0.3405 (determined by Montroll in 1964).  From A/D:

Drunkard: "Will I ever, ever get home again?"
Poyla: "You can't miss; just keep going and stay out of 3D."

If we now begin to wander in conformation space, I'd guess that one might
be able to construct an argument that "proves" that a "correct" structure
cannot be guessed if the constraints are sufficiently lax.  Perhaps within
certain boundaries, one may be able to get close.  I'd be interested to
hear the reaction of those more mathematically inclined.


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