title: Virulence of Streptococcus pneumoniae: PsaA mutants are hypersensitive to oxidative stress.
abstract: psaA encodes a 37-kDa pneumococcal lipoprotein which is part of an ABC Mn(II) transport complex. Streptococcus pneumoniae D39 psaA mutants have previously been shown to be significantly less virulent than wild-type D39, but the mechanism underlying the attenuation has not been resolved. In this study, we have shown that psaA and psaD mutants are highly sensitive to oxidative stress, i.e., to superoxide and hydrogen peroxide, which might explain why they are less virulent than the wild-type strain. Our investigations revealed altered expression of the key oxidative-stress response enzymes superoxide dismutase and NADH oxidase in psaA and psaD mutants, suggesting that PsaA and PsaD may play important roles in the regulation of expression of oxidative-stress response enzymes and intracellular redox homeostasis.
authors.affiliation: Centre for Metals in Biology and Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Hsing-Ju
authors.initials: HJ
authors.lastname: Tseng
authors.forename: Alastair G
authors.initials: AG
authors.lastname: McEwan
authors.forename: James C
authors.initials: JC
authors.lastname: Paton
authors.forename: Michael P
authors.initials: MP
authors.lastname: Jennings
mesh_terms: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics*; D002413:Cations, Divalent / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000633:toxicity; D008074:Lipoproteins / Q000235:genetics*; D008345:Manganese / Q000494:pharmacology; D026901:Membrane Transport Proteins; D009097:Multienzyme Complexes / Q000032:analysis; D009154:Mutation; D009247:NADH, NADPH Oxidoreductases / Q000032:analysis; D018384:Oxidative Stress / Q000235:genetics*; D010269:Paraquat / Q000633:toxicity; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000472:pathogenicity*; D013482:Superoxide Dismutase / Q000235:genetics
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D002413:Cations, Divalent; D008074:Lipoproteins; D026901:Membrane Transport Proteins; D009097:Multienzyme Complexes; C085000:PsaA protein, Streptococcus; C115973:psaD protein, Streptococcus; D008345:Manganese; D006861:Hydrogen Peroxide; C095500:SodA protein, Bacteria; D013482:Superoxide Dismutase; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D010269:Paraquat