title: Sequence analysis of the beta-N-acetylhexosaminidase gene of Vibrio vulnificus: evidence for a common evolutionary origin of hexosaminidases.
abstract: DNA cloned from the marine bacterium Vibrio vulnificus into Escherichia coli HB101 can hydrolyze chitin oligomer analogs in the recipient. The nucleotide sequence of the cloned DNA was determined and a single long open reading frame of 2541 base pairs (initiation codon through termination codon) was found. The nucleotide sequence predicts a gene product of 847 amino acids and a molecular mass of 94.3 kDa. In vitro transcription and translation analyses indicated a single protein of 94 kDa encoded by the cloned DNA. The gene product hydrolyzes methylumbelliferyl beta-D conjugates of chitotriose, chitobiose, N-acetylglucosamine, and N-acetylgalactosamine and has, therefore, been termed a beta-N-acetylhexosaminidase. The predicted protein shares a high degree of sequence similarity with the chitobiase of Vibrio harveyi and limited similarity with the alpha chain of human beta-hexosaminidase. Cluster analyses suggest a common evolutionary ancestor for all known hexosaminidase enzymes, with no detectable relationship to known chitinases.
authors.affiliation: University of Maryland, Center of Marine Biotechnology, Maryland Biotechnology Institute, Baltimore 20742.
authors.forename: C C
authors.initials: CC
authors.lastname: Somerville
authors.forename: R R
authors.initials: RR
authors.lastname: Colwell
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D016000:Cluster Analysis; D005798:Genes, Bacterial / Q000235:genetics*; D006596:Hexosaminidases / Q000235:genetics; D008969:Molecular Sequence Data; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014733:Vibrio / Q000201:enzymology / Q000235:genetics*; D001619:beta-N-Acetylhexosaminidases / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D006596:Hexosaminidases; D001619:beta-N-Acetylhexosaminidases