Shelling the Voronoi interface of protein-protein complexes predicts residue activity and conservation

The accurate description of protein-protein interfaces remains a challenging task. Traditional criteria, based on atomic contacts or changes in solvent accessibility, tend to over or underpredict the interface itself and cannot discriminate active from less relevant parts. A recent simulation study by Mihalek and co-authors (2007, JMB 369, 584-95) concluded that active residues tend to be `dry', that is, insulated from water fluctuations. We show that patterns of `dry' residues can, to a large extent, be predicted by a fast, parameter-free and purely geometric analysis of protein interfaces. We introduce the shelling order of Voronoi facets as a straightforward quantitative measure of an atom's depth inside an interface. We analyze the correlation between Voronoi shelling order, dryness, and conservation on a set of 54 protein-protein complexes. Residues with high shelling order tend to be dry; evolutionary conservation also correlates with dryness and shelling order but, perhaps not surprisingly, is a much less accurate predictor of either property. Voronoi shelling order thus seems a meaningful and efficient descriptor of protein interfaces. Moreover, the strong correlation with dryness suggests that water dynamics within protein interfaces may, in first approximation, be described by simple diffusion models

Exploring Socio-Cultural Barriers to Facility-Based Childbirth in Sub-Saharan Africa: A Semi-Systematic Literature Review

M.Phil. in Global Health - ThesisINTH395AMAMD-GLO

Le diaphane et les ténèbres. Corps de lumière dans La charrette fantôme de Victor Sjöström

La charrette fantôme (Victor Sjöström, Suède, 1919) est le premier film fantastique jamais réalisé. La lumière, y tenant un rôle paradoxal et ambivalent, conduit l’image cinématographique aux limites de la représentation, sur les terres de l’inquiétante étrangeté. Sjöström, héritier des traditions figuratives de la photographie spirite et du tableau vivant, use de la lumière pour construire un espace, un temps et des corps capables de s’affranchir des lois régissant notre monde : la transparence se change en ombre, le diaphane se fait ténèbres, le halo de sainteté devient un bouclier de Persée qui menace le visible, entre cécité et éblouissement

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Eesti Arst 2022; 101(5):277–27