Computational and Applied Math Proseminar

Friday, October 26, 2:40 p.m. PSA 206

Alain Goriely

Program in Applied Mathematics and BIO5 Institute, UofA

Geometry and Mechanics of Proteins with Applications to Helical Repeats and Coiled-Coils

Abstract A protein fold is usually represented by the position of their $C_\alpha$. Some of these folds can be obtained accurately by experimental procedure such as X-ray crystallography. In this talk I introduce a continuous representation of protein folds that can be used to gain some insight on the geometry of proteins and consider large deformations and transformations of protein folds. The basic idea is to represent a protein fold as a sequence of helices passing through the $C_\alpha$ 's. This approach, which raises many interesting geometric questions, is particularly well-suited to study either proteins with repetitive sequences or coiled-coils.

In the first part of the talk I will develop the geometry and mechanics of protein structure and show how it can be used to relate existing proteins through evolutionary paths or build proto-proteins which are possible candidates for protein design. In the second part of the talk, I will study the mechanics and elasticity of proteins on large scales. In particular, I will show how it can be applied to fibrous proteins such as collagen and keratin which are made of helical proteins wound together to form coiled-coils. These superstructures have themselves a handedness dictated by the position of residues, external loadings, and their folding. I will revisit and generalize classical results by Crick to understand the chirality and mechanics of these structures and apply these ideas to the function of ATP-synthase and Adiponectin, an adipocyte hormone that can improve the body's response to insulin.

For further information please contact: mittelmann@asu.edu