Experimental evidence for the essential role of the C-terminal residue in the strict aminopeptidase activity of the thiol aminopeptidase PepC, a bacterial bleomycin hydrolase.
PepCs isolated from lactic acid bacteria and bleomycin hydrolases of eukaryotic organisms are strict aminopeptidases which belong to the papain family of thiol peptidases. The structural basis of the enzymic specificity of the lactococcal PepC has been investigated by site-directed mutagenesis. The deletion of the C-terminal residue (Ala-435) abolished the aminopeptidase activity, whereas this deletion led to a new peptidase specificity. The enzymic properties of wild-type and mutant PepCs demonstrate that the terminal alpha-carboxy group plays a key role in the strict aminopeptidase activity.
Mata
L
L
INRA, Unité de Recherche Biochimie et Structure des Protéines, 78352 Jouy-en-Josas cedex, France.
Erra-Pujada
M
M
Gripon
J C
JC
Mistou
M Y
MY
D000409:Alanine / Q000235:genetics; D000626:Aminopeptidases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016384:Consensus Sequence; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D013294:Lactococcus lactis / Q000201:enzymology*; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D011480:Protease Inhibitors / Q000494:pharmacology; D011489:Protein Denaturation; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D013379:Substrate Specificity
D011480:Protease Inhibitors; D011994:Recombinant Proteins; D000626:Aminopeptidases; C086319:PepC thiol aminopeptidase; D003546:Cysteine Endopeptidases; C031262:bleomycin hydrolase; D007930:Leucine; D000409:Alanine; C024974:E 64