The structure of bypass of forespore C, an intercompartmental signaling factor during sporulation in Bacillus.
Sporulation in Bacillus subtilis begins with an asymmetric cell division giving rise to smaller forespore and larger mother cell compartments. Different programs of gene expression are subsequently directed by compartment-specific RNA polymerase sigma-factors. In the final stages, spore coat proteins are synthesized in the mother cell under the control of RNA polymerase containing sigma(K), (Esigma(K)). sigma(K) is synthesized as an inactive zymogen, pro-sigma(K), which is activated by proteolytic cleavage. Processing of pro-sigma(K) is performed by SpoIVFB, a metalloprotease that resides in a complex with SpoIVFA and bypass of forespore (Bof)A in the outer forespore membrane. Ensuring coordination of events taking place in the two compartments, pro-sigma(K) processing in the mother cell is delayed until appropriate signals are received from the forespore. Cell-cell signaling is mediated by SpoIVB and BofC, which are expressed in the forespore and secreted to the intercompartmental space where they regulate pro-sigma(K) processing by mechanisms that are not yet fully understood. Here we present the three-dimensional structure of BofC determined by solution state NMR. BofC is a monomer made up of two domains. The N-terminal domain, containing a four-stranded beta-sheet onto one face of which an alpha-helix is packed, closely resembles the third immunoglobulin-binding domain of protein G from Streptococcus. The C-terminal domain contains a three-stranded beta-sheet and three alpha-helices in a novel domain topology. The sequence connecting the domains contains a conserved DISP motif to which mutations that affect BofC activity map. Possible roles for BofC in the sigma(K) checkpoint are discussed in the light of sequence and structure comparisons.
Patterson
Hayley M
HM
Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5YW, United Kingdom.
Brannigan
James A
JA
Cutting
Simon M
SM
Wilson
Keith S
KS
Wilkinson
Anthony J
AJ
Ab
Eiso
E
Diercks
Tammo
T
de Jong
Rob N
RN
Truffault
Vincent
V
Folkers
Gert E
GE
Kaptein
Robert
R
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000502:physiology*; D002450:Cell Communication; D002462:Cell Membrane / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D021241:Spectrometry, Mass, Electrospray Ionization; D013171:Spores, Bacterial / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000737:chemistry / Q000502:physiology*
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C104572:BofC protein, Bacillus subtilis; D011994:Recombinant Proteins; D014157:Transcription Factors; D012321:DNA-Directed RNA Polymerases