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bioRxiv · 10.1101/405365

Zinc-binding to the cytoplasmic PAS domain regulates the essential WalK histidine kinase of Staphylococcus aureus

Monk, I. R.·Shaikh, N.·Begg, S. L.·Gajdiss, M.·Lee, J. Y. H.·Pidot, S. J.·Seemann, T.·Kuiper, M.·Winnen, B.·Hvorup, R.·Collins, B. M.·Bierbaum, G.·Howden, B. P.·McDevitt, C. A.·King, G. F.·Stinear, T. P.
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Abstract

WalKR (YycFG) is the only essential two-component regulator in the human pathogen Staphylococcus aureus. WalKR regulates peptidoglycan synthesis, but this function alone appears not to explain its essentiality. To understand WalKR function we investigated a suppressor mutant that arose when WalKR activity was impaired; a single histidine to tryptophan substitution (H271Y) in the cytoplasmic Per-Arnt-Sim (PASCYT) domain of the histidine kinase WalK. Introduction of the WalKH271Y mutation into wild-type S. aureus activated the WalKR regulon. Structural analyses of the WalK PASCYT domain revealed a hitherto unknown metal binding site, in which a zinc ion (Zn2+) was tetrahedrally-coordinated by four amino acid residues including H271. The WallkH271Y mutation abrogated metal binding, increasing WalK kinase activity and WalR phosphorylation. Thus, Zn2+-binding negatively regulates WalKR activity. Identification of a metal ligand sensed by the WalKR system substantially expands our understanding of this critical S. aureus regulon.

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Monk, I. R., Shaikh, N., Begg, S. L., Gajdiss, M., Lee, J. Y. H., Pidot, S. J., Seemann, T., Kuiper, M., Winnen, B., Hvorup, R., Collins, B. M., Bierbaum, G., Howden, B. P., McDevitt, C. A., King, G. F., Stinear, T. P.. 2018-08-31. Zinc-binding to the cytoplasmic PAS domain regulates the essential WalK histidine kinase of Staphylococcus aureus. https://doi.org/10.1101/405365

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