SPD1590_iTRAQ - A Novel Iron Transporter SPD_1590 in Streptococcus pneumoniae Contributing to Bacterial Virulence Properties

Streptococcus pneumoniae has three main transporters for iron acquisition: PiaABC, PiuABC, and PitABC. Our previous study had shown that the mRNA and protein levels of SPD_1590 are significantly upregulated in a piuA/piaA/pitA triple mutant, suggesting that SPD_1590 might be a novel iron transporter in S. pneumoniae. In the present work, using spd1590-deleted and -overexpressing strains and the purified SPD_1590 protein, we show that SPD_1590 can bind hemin. Furthermore, the results of iTRAQ quantitative proteomics and cell-infection studies demonstrate that, similarly to other metal-ion uptake proteins, SPD_1590 is important for bacterial virulence.