Structure-function analysis of the Bacillus megaterium GerUD spore germinant receptor protein.
Germination of Bacillus spores is triggered by the interaction of germinant molecules with specialized receptor proteins localized to the spore inner membrane. Germinant receptors (GRs) are comprised typically of three interacting protein subunits, each of which is essential for receptor function. At least some GRs appear to have a fourth component, referred to as a D-subunit protein. A number of D-subunit proteins were shown previously to be capable of modulating the activity of associated GRs. Here, we investigate the topology and structure-function relationships of the Bacillus megaterium QM B1551 GerUD protein, which is associated with the GerU GR. The presented data demonstrate that GerUD can be subjected to relatively extensive structural modifications while retaining function. Indeed, the presence of either of the two transmembrane spanning domains is sufficient to modulate an efficient GerU-mediated germinative response. The precise function of D-subunit proteins has yet to be established, although they may act as molecular chaperones within the spore inner-membrane environment.
Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, UK.
Srishti
S
Gupta
Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, UK.
Ke Xu
KX
Zhou
Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, UK.
David M D
DM
Bailey
Department of Chemical Engineering and Biotechnology, Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, UK gc301@cam.ac.uk.
Graham
G
Christie
D001410:Bacillus megaterium / Q000737:chemistry* / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D009154:Mutation; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics; D013171:Spores, Bacterial / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D008565:Membrane Proteins; D021122:Protein Subunits
Bacillus; D-subunit; germinant receptor; germination; spores