The power of being at the interface: mechanism of DesK thermosensing

CYBULSKI LARISA ESTEFANÍA

Congreso; XLII Reunión Annual de la Sociedad Argentina de Biofísica; 2013

The thermosensor DesK is a five-pass transmembrane (TM) histidine kinase that senses and signals temperature changes in Bacillus. Temperature sensing involves a built-in instability caused by two motifs of hydrophilic residues located at both, the N-terminus and C-terminus of the TM domain. The N-terminus has two hydrophilic amino acids (K10 and N12) below the lipid/water interface, and the C-terminus has a hydrophilic motif composed of three serines located on one side of the helix. These interfacial hydrophilic motifs render the protein sensitive to membrane thickness and to the extent of interfacial hydration, which would in turn depend upon temperature changes. A conformational change in the linker connecting the TM sensing domain with the cytoplasmic catalytic domain is triggered by the interplay of these interfacial motifs to control DesK activity.