Bronstein, A. M. | bioRxiv Science

bioRxiv2023

Water stabilizes an alternate turn conformation in horse heart myoglobin

Comparison of myoglobin structures reveals that protein isolated from horse heart consistently adopts an alternate turn conformation in comparison to its homologues. Analysis of hundreds of high-resolution structures discounts crystallization conditions or the surrounding amino acid protein environment as explaining this difference, that is also not captured by the AlphaFold prediction. Rather, a water molecule is identified as stabilizing the conformation in the horse heart structure, which immediately reverts to the whale conformation in molecular dynamics simulations excluding that structural water.

cell biology↗

bioRxiv2022

Defining amino acid pairs as structural units suggests mutation sensitivity toadjacent residues

Proteins fold from chains of amino acids, forming secondary structures, -helices and {beta}-strands, that, at least for globular proteins, subsequently fold into a three-dimensional structure. A large-scale analysis of high-resolution protein structures suggests that amino acid pairs constitute another layer of ordered structure, more local than these conventionally defined secondary structures. We develop a cross-peptide-bond Ramachandran plot that captures the conformational preferences of the amino acid pairs and show that the effect of a particular mutation on the stability of a protein depends in a predictable manner on the adjacent amino acid context. One-Sentence SummaryLarge-scale protein backbone analysis reveals amino acid pair conformational preferences and predicts how sequence context affects mutant stability.

molecular biology↗