20.110_pset5_fall2008

20.110_pset5_fall2008 - 1 PS#5 20.110/2.772 Fall 2008...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 PS#5 20.110/2.772 Fall 2008 2.772/20.110 Problem Set #5 Due Friday October 17 in 16-429 at 3pm NO LATE PSETS WILL BE ACCEPTED Please submit the problems as: 2, 4 3,5, 7 6 ,9, 10 1, 8 1.) ELVIS is everywhere a.) Given 20 naturally occurring amino acids, what is the probability that the amino acid sequence ELVIS occurs in a stretch of a protein sequence? b.) What is the probability if the order of the amino acids did not matter, i.e., VLSEI, etc.? 2.) Levinthals Paradox: Cyrus Levinthal, a former MIT professor, claimed that proteins can not go from unfolded to folded state by sampling of all possible states. He claimed that it would take way too long for a protein to fold if they were to sample all possible conformations (proteins fold on the order of ~ms to ~ s). Assume that a protein has 100 amino acids and each amino acid has two degrees of freedom (angles of rotation called and ), also assume that it takes a femtosecond to sample each conformation. Using simple statistics show that Prof. Levinthal was indeed right and that it would take a very long time (much longer than our lifetimes!) if the protein was to sample all possible conformations. If proteins were to fold by sampling all possible states, calculate the change in entropy upon folding, assume that the unfolded state has all the possible states and the folded state is unique (i.e there is only one folded state). (Hint : Use Boltzmanns definition of entropy). 3.) The statistical thermodynamics of a cooperative system. (Dill and Bromberg) Perhaps the simplest statistical mechanical system having cooperativity is the three-level system in the following table....
View Full Document

Page1 / 4

20.110_pset5_fall2008 - 1 PS#5 20.110/2.772 Fall 2008...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online