Structural highlights
Publication Abstract from PubMedWild-type and variant forms of HpmA265 (truncated hemolysin A) from Proteus mirabilis reveal a right-handed, parallel beta-helix capped and flanked by segments of antiparallel beta-strands. The low-salt crystal structures form a dimeric structure via the implementation of on-edge main-chain hydrogen bonds donated by residues 243-263 of adjacent monomers. Surprisingly, in the high-salt structures of two variants, Y134A and Q125A-Y134A, a new dimeric interface is formed via main-chain hydrogen bonds donated by residues 203-215 of adjacent monomers, and a previously unobserved tetramer is formed. In addition, an eight-stranded antiparallel beta-sheet is formed from the flap regions of crystallographically related monomers in the high-salt structures. This new interface is possible owing to additional proteolysis of these variants after Tyr240. The interface formed in the high-salt crystal forms of hemolysin A variants may mimic the on-edge beta-strand positioning used in template-assisted hemolytic activity. Proteolysis of truncated hemolysin A yields a stable dimerization interface.,Novak WR, Bhattacharyya B, Grilley DP, Weaver TM Acta Crystallogr F Struct Biol Commun. 2017 Mar 1;73(Pt 3):138-145. doi:, 10.1107/S2053230X17002102. Epub 2017 Feb 21. PMID:28291749[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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