title: Structure and function of the oxidoreductase DsbA1 from Neisseria meningitidis.
abstract: Neisseria meningitidis encodes three DsbA oxidoreductases (NmDsbA1-NmDsbA3) that are vital for the oxidative folding of many membrane and secreted proteins, and these three enzymes are considered to exhibit different substrate specificities. This has led to the suggestion that each N. meningitidis DsbA (NmDsbA) may play a specialized role in different stages of pathogenesis; however, the molecular and structural bases of the different roles of NmDsbAs are unclear. With the aim of determining the molecular basis for substrate specificity and how this correlates to pathogenesis, we undertook a biochemical and structural characterization of the three NmDsbAs. We report the 2.0-A-resolution crystal structure of the oxidized form of NmDsbA1, which adopted a canonical DsbA fold similar to that observed in the structures of NmDsbA3 and Escherichia coli DsbA (EcDsbA). Structural comparisons revealed variations around the active site and candidate peptide-binding region. Additionally, we demonstrate that all three NmDsbAs are strong oxidases with similar redox potentials; however, they differ from EcDsbA in their ability to be reoxidized by E. coli DsbB. Collectively, our studies suggest that the small structural differences between the NmDsbA enzymes and EcDsbA are functionally significant and are the likely determinants of substrate specificity.
authors.affiliation: The Protein Crystallography Unit, Australian Research Council Center of Excellence in Structural and Functional Microbial Genomics, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Julian P
authors.initials: JP
authors.lastname: Vivian
authors.forename: Jessica
authors.initials: J
authors.lastname: Scoullar
authors.forename: Kieran
authors.initials: K
authors.lastname: Rimmer
authors.forename: Simon R
authors.initials: SR
authors.lastname: Bushell
authors.forename: Travis
authors.initials: T
authors.lastname: Beddoe
authors.forename: Matthew C J
authors.initials: MC
authors.lastname: Wilce
authors.forename: Emma
authors.initials: E
authors.lastname: Byres
authors.forename: Tristan P
authors.initials: TP
authors.lastname: Boyle
authors.forename: Bradley
authors.initials: B
authors.lastname: Doak
authors.forename: Jamie S
authors.initials: JS
authors.lastname: Simpson
authors.forename: Bim
authors.initials: B
authors.lastname: Graham
authors.forename: Begoña
authors.initials: B
authors.lastname: Heras
authors.forename: Charlene M
authors.initials: CM
authors.lastname: Kahler
authors.forename: Jamie
authors.initials: J
authors.lastname: Rossjohn
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Scanlon
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D029968:Escherichia coli Proteins / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000201:enzymology*; D010084:Oxidation-Reduction; D011485:Protein Binding; D019704:Protein Disulfide-Isomerases / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D029968:Escherichia coli Proteins; D019704:Protein Disulfide-Isomerases; C526648:dsbA protein, E coli