Structural and biochemical characterization of the oxidoreductase NmDsbA3 from Neisseria meningitidis

Julian Vivian, Jessica Scoullar, Amy Louise Robertson, Stephen Paul Bottomley, Henry James Horne, Ka-Yan Yanni Chin, Jerome Wielens, Philip Thompson, Tony Velkov, Susannah Piek, Emma Byres, Travis Clarke Beddoe, Matthew CJ Wilce, Charlene Maree Kahler, Jamie Rossjohn, Martin Scanlon

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19 Citations (Scopus)

Abstract

DsbA is an enzyme found in the periplasm of Gram-negative bacteria that catalyses the formation of disulfide bonds in a diverse array of protein substrates, many of which are involved in bacterial pathogenesis. Whilst most bacteria possess only a single essential DsbA, Neisseria meningitidis is unusual in that it possesses three DsbAs, although the reason for this additional redundancy is unclear. Two of these N. meningitidis enzymes (NmDsbA1 and NmDsbA2) play an important role in meningococcal attachment to human epithelial cells, whilst NmDsbA3 is considered to have a narrow substrate repertoire. To begin to address the role of DsbAs in the pathogenesis of N. meningitidis, we have determined the structure of NmDsbA3 to 2.3 A resolution. Although the sequence identity between NmDsbA3 and other DsbAs is low, the NmDsbA3 structure adopted a DsbA-like fold. Consistent with this finding, we demonstrated that NmDsbA3 acts as a thiol-disulfide oxidoreductase in vitro and is reoxidised by Escherichia coli DsbB (EcDsbB). However, pronounced differences in the structures between DsbA3 and EcDsbA, which are clustered around the active site of the enzyme, suggested a structural basis for the unusual substrate specificity that is observed for NmDsbA3.
Original languageEnglish
Pages (from-to)32452 - 32461
Number of pages10
JournalJournal of Biological Chemistry
Volume283
Issue number47
DOIs
Publication statusPublished - 2008

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