title: Sequence analysis, distribution and expression of an aminopeptidase N-encoding gene from Lactobacillus helveticus CNRZ32 [gene 155 (1995) 89-93].
abstract: Lactobacillus (Lb.) helveticus CNRZ32 possesses a 97-kDa metalloenzyme with aminopeptidase activity (PepN; EC 3.4.11.2). A 3.8-kb fragment encoding PepN was cloned into pIL253 and designated pSUW34. Transformation of Lactococcus (Lc.) lactis LM0230 with pSUW34 resulted in > 180-fold increase in general aminopeptidase (AP) activity using L-lysine-p-nitroanilide. Southern hybridization was conducted to determine the distribution of homology to the CNRZ32 pepN gene among lactic-acid bacteria (LAB). Hybridization was observed with strains of lactobacilli, pediococci, leuconostoc, streptococci and lactococci. The pepN gene was sequenced and found to encode a protein containing 844 amino acid (aa) residues. A comparison of Lb. helveticus CNRZ32 pepN to Lb. delbrueckii ssp. lactis DSM7290 pepN indicated 69.5% nucleotide (nt) identity and 71.8% aa identity, while comparison to pepN from Lc. lactis ssp. cremoris MG1363 indicated 61.1% nt identity and 49.2% aa identity. Alignment of peptidase aa sequences of LAB, Escherichia coli, yeast and mammalian origin display homology in the zinc-binding domain, as well as a conserved region upstream from the putative active site.
authors.affiliation: Department of Bacteriology, University of Wisconsin-Madison 53706, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Christensen
authors.forename: D L
authors.initials: DL
authors.lastname: Lin
authors.forename: A
authors.initials: A
authors.lastname: Palva
authors.forename: J L
authors.initials: JL
authors.lastname: Steele
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D018826:CD13 Antigens / Q000096:biosynthesis / Q000235:genetics*; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D007778:Lactobacillus / Q000201:enzymology / Q000235:genetics*; D008667:Metalloproteins; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D008667:Metalloproteins; D018826:CD13 Antigens