A mutational wrench in the HAMP gearbox.
HAMP domains communicate between input and output signalling elements in bacterial proteins. In the Tsr chemoreceptor, they convert axial movement of transmembrane helix 2 into changes in packing of the cytoplasmic kinase-control module (KCM). Zhou et al. suggest transmembrane helix 2 'tugs' on HAMP to destabilize x-da packing of the parallel four-helix bundle of the HAMP homodimer. Attractants would inhibit tugging. HAMP stability may be inversely related to stability of the a-d packing of the anti-parallel four-helix bundle of KCM, a relationship possibly facilitated by HAMP/KCM helical mismatch. The beauty of this idea lies in its simplicity and testability.
Manson
Michael D
MD
Department of Biology, Texas A and M University, College Station, TX 77843, USA. mike@mail.bio.tamu.edu
D018407:Bacterial Physiological Phenomena; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D008956:Models, Chemical; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D015398:Signal Transduction
D001426:Bacterial Proteins; D008565:Membrane Proteins; C057635:Tsr protein, Bacteria