PDBsum entry 5kf3

Toxin

PDB id: 5kf3

Contents

Protein chain

234 a.a.

Waters ×165

References listed in PDB file

Key reference

• Title: Proteolysis of truncated hemolysin a yields a stable dimerization interface.
• Authors: W.R.Novak, B.Bhattacharyya, D.P.Grilley, T.M.Weaver.
• Ref.: Acta Crystallogr F Struct Biol Commun, 2017, 73, 138-145.
• PubMed id: 28291749

Abstract

Wild-type and variant forms of HpmA265 (truncated hemolysin A) from Proteus mirabilis reveal a right-handed, parallel β-helix capped and flanked by segments of antiparallel β-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 β-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 β-strand positioning used in template-assisted hemolytic activity.