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Molecular Characterization and Functional Analysis of a secA Gene Homolog in Actinobacillus actinomycetemcomitans
Author(s) -
Novak Karen F.,
nemacher Michael R.,
Pourhamidi Jaleh
Publication year - 2000
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2000.tb01257.x
Subject(s) - biology , gene , escherichia coli , microbiology and biotechnology , gene product , nucleic acid sequence , homology (biology) , peptide sequence , sequence analysis , molecular cloning , actinobacillus , genetics , gene expression , bacteria
Results of Southern blot analyses and polymerase chain reaction revealed that the Gram‐negative pathogen, Actinobacillus actinomycetemcomitans , harbored DNA homologous to the secA gene of Escherichia coli . In E. coli , the secA gene product is essential for translocation of proteins across the inner membrane via the Sec system. This A. actinomycetemcomitans secA homolog was cloned and its nucleotide sequence determined. Amino acid sequence analysis of the cloned gene revealed significant homology to the SecA proteins of Haemophilus influenzae, E. coli, Caulobacter crescentus and Bacillus subtilis . Although the cloned gene did not complement a temperature sensitive mutation in the E. coli secA gene, strains harboring the cloned gene did produce a protein that cross‐reacted with anti‐SecA antibody. In addition, the cloned gene did restore sensitivity to sodium azide in an E. coli azide R mutant. These data support the hypothesis that A. actinomycetemcomitans may use a system similar to the Sec system of E. coli to transport proteins across the cytoplasmic membrane, but suggest that the A. actinomycetemcomitans gene product may require genera‐specific Sec proteins to complement some Sec mutations in E. coli .