Impact of a Point Mutation in a Protein Structure
Résumé
Proteins are involved in most cellular functions at all levels, from DNA duplication to chemical metabolism, cell structuring and signal transmission. “Water-soluble” proteins fold into a compact globular form (unlike fibrous, membrane and “disordered” proteins). The hydrophobic nature of certain amino acids makes this compact folding necessary. Proteins are said to be “marginally stable”: typically, there is a difference of 3–7 kcal/mol in free folding energy between folded and unfolded conformations. The substitution of one amino acid by another (a mutation) is one of the fundamental events of molecular evolution, with variable consequences in proteins. In order to determine whether Root-Mean-Square Deviations tend to be larger in terms of mutations, it is necessary to be able to compare several structures that only differ from each other by a single point mutation.