All-atom 3D structure prediction of transmembrane β-barrel proteins from sequences Journal Article


Authors: Hayat, S.; Sander, C.; Marks, D. S.; Elofsson, A.
Article Title: All-atom 3D structure prediction of transmembrane β-barrel proteins from sequences
Abstract: Transmembrane β-barrels (TMBs) carry out major functions in substrate transport and protein biogenesis but experimental determination of their 3D structure is challenging. Encouraged by successful de novo 3D structure prediction of globular and α-helical membrane proteins from sequence alignments alone, we developed an approach to predict the 3D structure of TMBs. The approach combines the maximum-entropy evolutionary coupling method for predicting residue contacts (EVfold) with a machine-earning approach (boctopus2) for predicting β-strands in the barrel. In a blinded test for 19 TMB proteins of known structure that have a sufficient number of diverse homologous sequences available, this combined method (EVfold-bb) predicts hydrogen-bonded residue pairs between adjacent β-strands at an accuracy of ∼70%. This accuracy is sufficient for the generation of all-atom 3D models. In the transmembrane barrel region, the average 3D structure accuracy [template-modeling (TM) score] of top-ranked models is 0.54 (ranging from 0.36 to 0.85), with a higher (44%) number of residue pairs in correct strand-strand registration than in earlier methods (18%). Although the nonbarrel regions are predicted less accurately overall, the evolutionary couplings identify some highly constrained loop residues and, for FecA protein, the barrel including the structure of a plug domain can be accurately modeled (TM score = 0.68). Lower prediction accuracy tends to be associated with insufficient sequence information and we therefore expect increasing numbers of β-barrel families to become accessible to accurate 3D structure prediction as the number of available sequences increases. © 2015, National Academy of Sciences. All rights reserved.
Keywords: unclassified drug; protein analysis; protein interaction; three dimensional imaging; membrane protein; hydrogen bond; hydrogen bonding; protein folding; protein structure; protein family; priority journal; article; de novo 3d structure prediction; evolutionary couplings; maximum-entropy analysis; transmembrane β-barrels; transmembrane beta barrel protein
Journal Title: Proceedings of the National Academy of Sciences of the United States of America
Volume: 112
Issue: 17
ISSN: 0027-8424
Publisher: National Academy of Sciences  
Date Published: 2015-04-28
Start Page: 5413
End Page: 5418
Language: English
DOI: 10.1073/pnas.1419956112
PROVIDER: scopus
PMCID: PMC4418893
PUBMED: 25858953
DOI/URL:
Notes: Export Date: 3 June 2015 -- Source: Scopus
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  1. Chris Sander
    210 Sander
  2. Sikander Hayat
    5 Hayat