Iron content of Streptococcus suis and evidence for a dpr homologue.
The type strain of Streptococcus suis was investigated for features that might help the organism to tolerate the H2O2 that is produced during growth. Enzyme assays, using soluble extracts, revealed that the type strain, which lacks catalase, lacks NADH peroxidase in both the mid-exponential and stationary phases of the growth cycle. Although iron could not be detected colourimetrically in dense cell suspensions, determination of the cellular iron content following growth to early stationary phase in the presence of 55FeCl3 demonstrated that S. suis does contain iron and hence is incapable of iron exclusion. Gene amplification, using oligonucleotide primers based on dpr of Streptococcus mutans, followed by nucleotide sequencing, revealed in S. suis, the presence of a gene that encodes a Dpr homologue. It is concluded that in S. suis, tolerance of H2O2 is due to iron sequestration by Dpr and the consequent effect of this process on the extent of Fenton chemistry.
Niven
D F
DF
Department of Natural Resource Sciences, McGill University, Ste. Anne de Bellevue, QC, Canada. niven@nrs.mcgill.ca
Ekins
A
A
D001426:Bacterial Proteins / Q000032:analysis*; D001483:Base Sequence; D001692:Biological Transport; D004268:DNA-Binding Proteins; D004352:Drug Resistance, Microbial; D005798:Genes, Bacterial; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D010545:Peroxides / Q000494:pharmacology*; D017011:Streptococcus suis / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C414750:Dpr protein, Streptococcus; C045076:Fenton's reagent; D010545:Peroxides; D006861:Hydrogen Peroxide; D007501:Iron