RT Journal Article SR Electronic(1) A1 Lovatt, A. A1 Roberts, I. S.YR 1994 T1 Cloning and expression in Escherichia coliof the nahAgene from Porphyromonas gingivalisindicates that β-N-acetylhexosaminidase is an outer-membrane-associated lipoprotein JF Microbiology, VO 140 IS 12 SP 3399 OP 3406 DO https://doi.org/10.1099/13500872-140-12-3399 PB Microbiology Society, SN 1465-2080, AB Porphyromonas gingivalishas been implicated in human periodontal diseases. It expresses a number of exoglycosidase enzymes capable of hydrolysing host proteoglycan residues. As a first stage to explore the role of these enzymes in periodontal tissue damage, the nahAgene of P. gingivalisW83, which encodes β-N-acetylhexosaminidase (β-Nahase), was cloned. The gene was expressed poorly in Escherichia coli, but increased expression was achieved by cloning the nahAgene downstream of the tac promoter. Southern blot analysis revealed that nahAwas present as a single copy, and it was found in all the other P. gingivalisstrains tested. In contrast, sequences homologous to nahAwere not detected in either P. endodontalisor P. asaccharolytica.The nahAgene was 2331 bp long and encoded a β-Nahase enzyme of 777 amino acids with a predicted molecular mass of 87 kDa. A characteristic signal peptide for an acylated lipoprotein was present at the amino-terminus, suggesting that the mature β-Nahase is a lipoprotein. The predicted amino acid sequence of the P. gingivalisβ-Nahase shared homology with the catalytic domains of the human β-Nahase enzyme and the chitinase of Vibrio harveyi, suggesting a common catalytic mechanism., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/13500872-140-12-3399