The periplasmic endonuclease I of Escherichia coli has amino-acid sequence homology to the extracellular DNases of Vibrio cholerae and Aeromonas hydrophila.
The gene endA, encoding the periplasmic endonuclease I (EndoI) of Escherichia coli, was identified on a cloned chromosomal 1.5-kb HindIII fragment. The nucleotide sequence of the fragment revealed an open reading frame (ORF) coding for a polypeptide of 235 amino acids (aa). The ORF preceeded by a region with two possible promoter sites displays promoter activity when cloned into an expression vector. On the C-terminal side, two sequences with putative transcription termination function are present. The predicted aa sequence suggests the presence of a signal peptide of 22 aa and a signal peptide cleavage site. A cold-shock supernatant from cells harbouring a multicopy endA+ plasmid contained an approx. tenfold higher amount than wild-type cells of the DNA double-strand- and single-strand-cleavage activities characteristic of EndoI. The growth rate and viability of the cells was not affected. The predicted aa sequence of the ORF is 60 and 54% identical to the sequence of extracellular DNases from Vibrio cholerae and Aeromonas hydrophila, respectively.
Jekel
M
M
Universität Oldenburg, Germany.
Wackernagel
W
W
D016980:Aeromonas hydrophila / Q000201:enzymology*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001483:Base Sequence; D003851:Deoxyribonucleases / Q000737:chemistry*; D004706:Endodeoxyribonucleases / Q000737:chemistry*; D004926:Escherichia coli / Q000201:enzymology*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013728:Terminator Regions, Genetic; D014734:Vibrio cholerae / Q000201:enzymology*
D001426:Bacterial Proteins; D008565:Membrane Proteins; D003851:Deoxyribonucleases; D004706:Endodeoxyribonucleases; C064668:endA protein, bacteria