Highly sensitive and selective colorimetric determination ofStaphylococcus aureus viachicken anti-protein A IgY antibody

Utilization of chicken anti-protein A IgY as an antibody pair for sensitive and selective detection ofS. aureus.

An “OFF–ON” quantum dot–graphene oxide bioprobe for sensitive detection of micrococcal nuclease ofStaphylococcus aureus

mAb-Strep-QDs-GO probe in an OFF state due to energy transfer from QDs to GO turns into an ON state when the energy transfer is inhibited by MNase, thus allowing the sensing of MNase (Micrococcal Nuclease, an extracellular endonuclease ofStaphylococcus Aureus).

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

ABSTRACTWalKR (YycFG) is the only essential two-component regulator in the human pathogenStaphylococcus 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 WalKH271Ymutation into wild-typeS.aureusactivated the WalKR regulon. Structural analyses of the WalK PASCYTdomain revealed a hitherto unknown metal binding site, in which a zinc ion (Zn2+) was tetrahedrally-coordinated by four amino acid residues including H271. The WallkH271Ymutation 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 criticalS.aureusregulon.