Characterization of two new aminopeptidases in Escherichia coli.
Two genes in the Escherichia coli genome, ypdE and ypdF, have been cloned and expressed, and their products have been purified. YpdF is shown to be a metalloenzyme with Xaa-Pro aminopeptidase activity and limited methionine aminopeptidase activity. Genes homologous to ypdF are widely distributed in bacterial species. The unique feature in the sequences of the products of these genes is a conserved C-terminal domain and a variable N-terminal domain. Full or partial deletion of the N terminus in YpdF leads to the loss of enzymatic activity. The conserved C-terminal domain is homologous to that of the methionyl aminopeptidase (encoded by map) in E. coli. However, YpdF and Map differ in their preference for the amino acid next to the initial methionine in the peptide substrates. The implication of this difference is discussed. ypdE is the immediate downstream gene of ypdF, and its start codon overlaps with the stop codon of ypdF by 1 base. YpdE is shown to be a metalloaminopeptidase and has a broad exoaminopeptidase activity.
Zheng
Yu
Y
Bioinformatics Graduate Program, Boston University, Massachusetts 02215, USA. zhengy@neb.com
Roberts
Richard J
RJ
Kasif
Simon
S
Guan
Chudi
C
D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002413:Cations, Divalent / Q000378:metabolism; D018387:Codon, Initiator; D017124:Conserved Sequence; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D008670:Metals / Q000378:metabolism; D063208:Methionyl Aminopeptidases; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D016296:Mutagenesis; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
D002413:Cations, Divalent; D018387:Codon, Initiator; D029968:Escherichia coli Proteins; D008670:Metals; D000626:Aminopeptidases; D063208:Methionyl Aminopeptidases