DNA polymerases of low-GC gram-positive eubacteria: identification of the replication-specific enzyme encoded by dnaE.
dnaE, the gene encoding one of the two replication-specific DNA polymerases (Pols) of low-GC-content gram-positive bacteria (E. Dervyn et al., Science 294:1716-1719, 2001; R. Inoue et al., Mol. Genet. Genomics 266:564-571, 2001), was cloned from Bacillus subtilis, a model low-GC gram-positive organism. The gene was overexpressed in Escherichia coli. The purified recombinant product displayed inhibitor responses and physical, catalytic, and antigenic properties indistinguishable from those of the low-GC gram-positive-organism-specific enzyme previously named DNA Pol II after the polB-encoded DNA Pol II of E. coli. Whereas a polB-like gene is absent from low-GC gram-positive genomes and whereas the low-GC gram-positive DNA Pol II strongly conserves a dnaE-like, Pol III primary structure, it is proposed that it be renamed DNA polymerase III E (Pol III E) to accurately reflect its replicative function and its origin from dnaE. It is also proposed that DNA Pol III, the other replication-specific Pol of low-GC gram-positive organisms, be renamed DNA polymerase III C (Pol III C) to denote its origin from polC. By this revised nomenclature, the DNA Pols that are expressed constitutively in low-GC gram-positive bacteria would include DNA Pol I, the dispensable repair enzyme encoded by polA, and the two essential, replication-specific enzymes Pol III C and Pol III E, encoded, respectively, by polC and dnaE.
Barnes
Marjorie H
MH
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester 01655, USA.
Miller
Shelley D
SD
Brown
Neal C
NC
D002384:Catalysis; D004257:DNA Polymerase II / Q000235:genetics / Q000302:isolation & purification*; D004258:DNA Polymerase III / Q000235:genetics / Q000302:isolation & purification*; D006094:Gram-Positive Bacteria / Q000201:enzymology*; D008970:Molecular Weight
C074904:DNA polymerase III, alpha subunit; D004257:DNA Polymerase II; D004258:DNA Polymerase III