Purification and characterization of the Streptococcus salivarius methionine aminopeptidase (MetAP).
Streptococcus salivarius methionine aminopeptidase (MetAP) was purified from a recombinant Escherichia coli strain containing the S. salivarius map gene, which codes for MetAP. S. salivarius map coded for a protein of 286 amino acids with a calculated molecular mass of 31,723 Da and a pI of 4.6. The native enzyme eluted from a Superdex column as a protein with a molecular mass of 30.6 kDa and cleaved N-terminal Met of peptide only when the penultimate amino acid was Gly, Ala, Ser, Val, Pro, or Thr. The enzyme was more active against tetrapeptides than tripeptides and did not recognize dipeptides. It required the presence of a metal cation for activity, with a preference for Co(2+) over Mn(2+). S. salivarius MetAP has a pH optimum of 8.0 and an optimal temperature at 50 degrees C. The S. salivarius protein had an extra sequence of 24 amino acids between two conserved aspartate residues involved in the coordination of the metal ion. A similar extra sequence is present in MetAP from other streptococci and from Lactococcus lactis, but not from other bacteria or eukaryotes.
Boufous
El Houssine
el H
Groupe de recherche en écologie buccale, Département de biochimie et de microbiologie, Faculté des sciences et de génie, and Faculté de médecine dentaire, Université Laval, Quebec, Canada G1K 7P4.
Vadeboncoeur
Christian
C
D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D063208:Methionyl Aminopeptidases; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013291:Streptococcus / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity
D011994:Recombinant Proteins; D000626:Aminopeptidases; D063208:Methionyl Aminopeptidases