Cloning and sequencing of the cell division gene pbpB, which encodes penicillin-binding protein 2B in Bacillus subtilis.
The pbpB gene, which encodes penicillin-binding protein (PBP) 2B of Bacillus subtilis, has been cloned, sequenced, mapped, and mutagenized. The sequence of PBP 2B places it among the class B high-molecular-weight PBPs. It appears to contain three functional domains: an N-terminal domain homologous to the corresponding domain of other class B PBPs, a penicillin-binding domain, and a lengthy carboxy extension. The PBP has a noncleaved signal sequence at its N terminus that presumably serves as its anchor in the cell membrane. Previous studies led to the hypothesis that PBP 2B is required for both vegetative cell division and sporulation septation. Its sequence, map site, and mutant phenotype support this hypothesis. PBP 2B is homologous to PBP 3, the cell division protein encoded by pbpB of Escherichia coli. Moreover, both pbpB genes are located in the same relative position within a cluster of cell division and cell wall genes on their respective chromosomes. However, immediately adjacent to the B. subtilis pbpB gene is spoVD, which appears to be a sporulation-specific homolog of pbpB. Inactivation of SpoVD blocked synthesis of the cortical peptidoglycan in the spore, whereas carboxy truncation of PBP 2B caused cells to grow as filaments. Thus, it appears that a gene duplication has occurred in B. subtilis and that one PBP has evolved to serve a common role in septation during both vegetative growth and sporulation, whereas the other PBP serves a specialized role in sporulation.
Yanouri
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Department of Biological Sciences, Southern Methodist University, Dallas, Texas 75275-0376.
Daniel
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RA
Errington
J
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Buchanan
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CE
D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial; D001412:Bacillus subtilis / Q000166:cytology / Q000235:genetics*; D001426:Bacterial Proteins; D001483:Base Sequence; D002352:Carrier Proteins; D002455:Cell Division / Q000235:genetics*; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006602:Hexosyltransferases / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D002267:Muramoylpentapeptide Carboxypeptidase; D016296:Mutagenesis; D016366:Open Reading Frames; D046915:Penicillin-Binding Proteins; D046928:Peptidoglycan Glycosyltransferase; D010458:Peptidyl Transferases / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals; D011994:Recombinant Proteins / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C478704:FtsI protein, E coli; D009097:Multienzyme Complexes; D046915:Penicillin-Binding Proteins; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D046928:Peptidoglycan Glycosyltransferase; D002267:Muramoylpentapeptide Carboxypeptidase