PMID:27031880

Citation	Tedde, V, Rosini, R and Galeotti, CL (2016) Zn2+ Uptake in Streptococcus pyogenes: Characterization of adcA and lmb Null Mutants. PLoS ONE 11:e0152835
Abstract	An effective regulation of metal ion homeostasis is essential for the growth of microorganisms in any environment and in pathogenic bacteria is strongly associated with their ability to invade and colonise their hosts. To gain a better insight into zinc acquisition in Group A Streptococcus (GAS) we characterized null deletion mutants of the adcA and lmb genes of Streptococcus pyogenes strain MGAS5005 encoding the orthologues of AdcA and AdcAII, the two surface lipoproteins with partly redundant roles in zinc homeostasis in Streptococcus pneumoniae. Null adcA and lmb mutants were analysed for their capability to grow in zinc-depleted conditions and were found to be more susceptible to zinc starvation, a phenotype that could be rescued by the addition of Zn2+ ions to the growth medium. Expression of AdcA, Lmb and HtpA, the polyhistidine triad protein encoded by the gene adjacent to lmb, during growth under conditions of limited zinc availability was examined by Western blot analysis in wild type and null mutant strains. In the wild type strain, AdcA was always present with little variation in expression levels between conditions of excess or limited zinc availability. In contrast, Lmb and HtpA were expressed at detectable levels only during growth in the presence of low zinc concentrations or in the null adcA mutant, when expression of lmb is required to compensate for the lack of adcA expression. In the latter case, Lmb and HtpA were overexpressed by several fold, thus indicating that also in GAS AdcA is a zinc-specific importer and, although it shares this function with Lmb, the two substrate-binding proteins do not show fully overlapping roles in zinc homeostasis.
Links	PubMed PMC4816340 Online version:10.1371/journal.pone.0152835
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
STRPY:Q7DII5	Contributes to	GO:0046872: metal ion binding	ECO:0000315:		F		Figures 4 shows wild-type lmb grew and knock-out lmb didn't grow in media containing ZnCl2.	complete CACAO 11822
STRPY:A0A0E1EP82	Contributes to	GO:0008270: zinc ion binding	ECO:0000315:		F		Figure 3 shows knock-out adcA mutant grew significantly less than wild-type adcA in zinc-containing media.	complete CACAO 11826

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