Evidence that SpoIVFB is a novel type of membrane metalloprotease governing intercompartmental communication during Bacillus subtilis sporulation.
Processing of pro-sigma(K) in the mother cell compartment of sporulating Bacillus subtilis involves SpoIVFB and is governed by a signal from the forespore. SpoIVFB has an HEXXH motif characteristic of metalloproteases embedded in one of its transmembrane segments. Several conservative single amino acid changes in the HEXXH motif abolished function. However, changing the glutamic acid residue to aspartic acid, or changing the isoleucine residue that precedes the motif to proline, permitted SpoIVFB function. Only one other putative metalloprotease, site 2 protease has been shown to tolerate aspartic acid rather than glutamic acid in its HEXXH sequence. Site 2 protease and SpoIVFB share a second region of similarity with a family of putative membrane metalloproteases. A conservative change in this region of SpoIVFB abolished function. Interestingly, SpoIVFA increased the accumulation of certain mutant SpoIVFB proteins but was unnecessary for accumulation of wild-type SpoIVFB.
Yu
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YT
Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824, USA.
Kroos
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D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D004252:DNA Mutational Analysis; D010450:Endopeptidases; D004795:Enzyme Stability; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008666:Metalloendopeptidases / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012097:Repressor Proteins; D012808:Sigma Factor / Q000378:metabolism; D015398:Signal Transduction; D013171:Spores, Bacterial; D014157:Transcription Factors / Q000378:metabolism
D001426:Bacterial Proteins; D008565:Membrane Proteins; D012097:Repressor Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C112176:pro-sigmaK protein, Bacillus subtilis; C071441:spoIVFA protein, Bacillus subtilis; D010450:Endopeptidases; D008666:Metalloendopeptidases; C071442:spoIVFB protein, Bacillus subtilis