Key structural elements for the signal transduction mechanism of DesK, a thermosensor histidine kinase

ALBANESI, DANIELA; TRAJTENBERG, FELIPE; TSAI, YI TING; ALZARI, PEDRO; BUSCHIAZZO, ALEJANDRO; DE MENDOZA, DIEGO

Salta

Congreso; 3rd Latin American Protein Society Meeting; 2010

Latin American Protein Society

DesK, a histidine kinase from Bacillus subtilis, is a membrane-bound thermosensor suited to remodel membrane fluidity when the temperature drops below~30°C. We have recently reported the crystal structure of the entire cytoplasmic region of DesK in three distinct functional states, proposing a model to account for the regulation mechanism of the catalytic activities of this protein along its catalytic cycle1. Comparison of these structures invited the hypothesis that contacts between the central dimerization histidine phosphotransfer domain (DHp) and the ATP-binding domains (ABDs), as well as a dynamic N-terminal coiled-coil, support a labile association to be released for autophosphorylation and maintained for the phosphatase activity, under control of the sensor domain upon signal perception. To test this hypothesis we have performed structure-based mutagenesis. In vivo studies with a set of DesK variants stress the relevance of these structural elements to control its output activity and confirm the importance of the rotational and shifting movements in the conserved DHp domain on the signal transduction mechanism of this sensor protein.       1. Albanesi D., Martín M., Trajtenberg F., Mansilla M.C., Haouz A., Alzari P.M., de Mendoza D. and Buschiazzo A., Proc Natl Acad Sci U S A, 106,16185-16190 (2009).We acknowledge the support of HHMI, CONICET and UNR