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  • The phosphohistidine phosphatase SixA dephosphorylates the phosphocarrier NPr.

The phosphohistidine phosphatase SixA dephosphorylates the phosphocarrier NPr.

The Journal of biological chemistry (2020-11-18)
Jane E Schulte, Manuela Roggiani, Hui Shi, Jun Zhu, Mark Goulian
ABSTRACT

Histidine phosphorylation is a posttranslational modification that alters protein function and also serves as an intermediate of phosphoryl transfer. Although phosphohistidine is relatively unstable, enzymatic dephosphorylation of this residue is apparently needed in some contexts, since both prokaryotic and eukaryotic phosphohistidine phosphatases have been reported. Here we identify the mechanism by which a bacterial phosphohistidine phosphatase dephosphorylates the nitrogen-related phosphotransferase system, a broadly conserved bacterial pathway that controls diverse metabolic processes. We show that the phosphatase SixA dephosphorylates the phosphocarrier protein NPr and that the reaction proceeds through phosphoryl transfer from a histidine on NPr to a histidine on SixA. In addition, we show that Escherichia coli lacking SixA are outcompeted by wild-type E. coli in the context of commensal colonization of the mouse intestine. Notably, this colonization defect requires NPr and is distinct from a previously identified in vitro growth defect associated with dysregulation of the nitrogen-related phosphotransferase system. The widespread conservation of SixA, and its coincidence with the phosphotransferase system studied here, suggests that this dephosphorylation mechanism may be conserved in other bacteria.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-N1-Phosphohistidine (1-pHis) Antibody, clone SC1-1, ZooMAb® Rabbit Monoclonal, recombinant, expressed in HEK 293 cells
Sigma-Aldrich
Anti-N3-Phosphohistidine (3-pHis) Antibody, clone SC56-2, ZooMAb® Rabbit Monoclonal, recombinant, expressed in HEK 293 cells
Sigma-Aldrich
TEV Protease