Impact of Single Amino Acid Substitution Upon Protein Structure

In the biological sciences, one of the most fundamental operations is that of comparison. As we strive to further understand the constituent parts of living tissue, we need to examine proteins and their many mutations. Indeed, characterising mutations is an important part of proteomics, because a seemingly trivial mutation can sometimes stand between creating a life-saving drug on one hand, or blocking a vital receptor inactivating that same drug on the other. In this work we examined single point mutations to characterise their effects on outwardly expanding neighbourhood ranges. As the shape of a protein is very important, we examined how mutations can make subtle changes to the protein shape as well as investigated the implications both for backbone and side-chain residues. Our findings suggest that structural changes upon a mutation are significantly influenced by the protein shape, which allows for the prediction of the impact brought about the mutation by looking only into the protein shape. Surprisingly, we found that there was very little variation between wild type and mutant protein structures close to the mutation site. Also, in contrast with what was expected, the largest structural variations were found when deleted and introduced residues had similar hydrophobicity.