The streptococcal iron uptake (Siu) transporter is required for iron uptake and virulence in a zebrafish infection model

摘要: A limited understanding of iron uptake mechanisms is available for Streptococcus pyogenes, a haemolytic human pathogen capable using variety haemoproteins in addition to ferric and ferrous iron. This study characterizes transporter named siu (for streptococcal uptake), which consists an ATP-binding protein (SiuA), substrate-binding (SiuD), two membrane permease subunits (SiuBG). An siuG mutant was constructed characterized. The demonstrated growth reduction comparison the parent strain when grown complex medium containing form blood, haemoglobin or serum. Only small observed However, assays showed decrease approximately 30 % Fe3+ incorporation. Addition 6 μM haem inhibited by wild-type 76 %, while protoporphyrin IX did not, suggesting that utilization as source responsible inhibition uptake. Inactivation moderately reduced ability inhibit incorporation cells. siaB (encoding second transporter) had similar outcome, inactivation both transporters cumulative effect. These observations implicate sia Strep. pyogenes. Studies zebrafish infection model revealed attenuated intramuscular intraperitoneal routes infection. Together these show system acquisition pathway pyogenes important vitro vivo.