Cloning and characterization of the haemolysin determinants from Aeromonas hydrophila |
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| Authors: | T AOKI I HIRONO |
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| Institution: | Department of Biological Resources. Faculty of Agriculture, Miyazaki University, Miyazaki, Japan |
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| Abstract: | Abstract. Two haemolysin genes (AHH4 and AHH-2) of Aeromonas hydrophila ATCC7966 were cloned into a plasmid vector in Escherichia coli K-12. An open reading frame (ORF) of the AHH-1 haemolysin gene was 1734 base pairs (bp). and corresponded to a protein of 577 amino acid residues. Analysis of the deduced amino sequence indicated a highly hydrophobic N-terminal region which had the characteristics of a leader peptide. The sequence also included the -10 region and the -35 region of a promoter, and a ribosome- binding site upstream from the ORF. The termination site was located downstream from the ORF. The haemolysin was a thermolabile protein with the predicted molecular mass of 60 kDa. The AHH-1 gene is distributed in various A. hydrophila and A. salmonicida strains. The nucleotide sequence of a 981 bp ORF of the AHH-2 gene was encoded with the predicted molecular mass of 377 kDa polypeptides. The homology of the nucleotide sequence was very low between the AHH-1 and AHH-2 genes, and also with the aerolysin gene cloned by Howard & Buckley (19S6). No leader peptide was found in the N-terminal region of the ORF of the AHH2 gene. The AHH-2 gene was detected in the original strain ATCC7966, but was not detected in other tested strains of A. hydrophila and A. salmonicida. |
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