Tripeptidase gene (pepT) of Lactococcus lactis: molecular cloning and nucleotide sequencing of pepT and construction of a chromosomal deletion mutant.
The gene encoding a tripeptidase (pepT) of Lactococcus lactis subsp. cremoris (formerly subsp. lactis) MG1363 was cloned from a genomic library in pUC19 and subsequently sequenced. The tripeptidase of L. lactis was shown to be homologous to PepT of Salmonella typhimurium with 47.4% identity in the deduced amino acid sequences. L. lactis PepT was enzymatically active in Escherichia coli and allowed growth of a peptidase-negative leucine-auxotrophic E. coli strain by liberation of Leu from a tripeptide. Using a two-step integration-excision system, a pepT-negative mutant of L. lactis was constructed. No differences between the growth of the mutant and that of the wild-type strain in milk or in chemically defined medium with casein as the sole source of essential amino acids were observed.
Mierau
I
I
Department of Genetics, University of Groningen, Haren, The Netherlands.
Haandrikman
A J
AJ
Velterop
O
O
Tan
P S
PS
Leenhouts
K L
KL
Konings
W N
WN
Venema
G
G
Kok
J
J
D000595:Amino Acid Sequence; D000626:Aminopeptidases; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D013294:Lactococcus lactis / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010447:Peptide Hydrolases / Q000096:biosynthesis / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000096:biosynthesis; D012486:Salmonella typhimurium / Q000235:genetics; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid
D011994:Recombinant Proteins; D010447:Peptide Hydrolases; D000626:Aminopeptidases; C023191:PepT tripeptidase