Prosegment of tripeptidyl peptidase I is a potent, slow-binding inhibitor of its cognate enzyme.
Tripeptidyl peptidase I (TPP I) is the first mammalian representative of a family of pepstatin-insensitive serine-carboxyl proteases, or sedolisins. The enzyme acts in lysosomes, where it sequentially removes tripeptides from the unmodified N terminus of small, unstructured polypeptides. Naturally occurring mutations in TPP I underlie a neurodegenerative disorder of childhood, classic late infantile neuronal ceroid lipofuscinosis (CLN2). Generation of mature TPP I is associated with removal of a long prosegment of 176 amino acid residues from the zymogen. Here we investigated the inhibitory properties of TPP I prosegment expressed and isolated from Escherichia coli toward its cognate protease. We show that the TPP I prosegment is a potent, slow-binding inhibitor of its parent enzyme, with an overall inhibition constant in the low nanomolar range. We also demonstrate the protective effect of the prosegment on alkaline pH-induced inactivation of the enzyme. Interestingly, the inhibitory properties of TPP I prosegment with the introduced classic late infantile neuronal ceroid lipofuscinosis disease-associated mutation, G77R, significantly differed from those revealed by wild-type prosegment in both the mechanism of interaction and the inhibitory rate. This is the first characterization of the inhibitory action of the sedolisin prosegment.
Golabek
Adam A
AA
Department of Developmental Neurobiology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, USA. adamgolabek@gmail.com
Dolzhanskaya
Natalia
N
Walus
Marius
M
Wisniewski
Krystyna E
KE
Kida
Elizabeth
E
D000626:Aminopeptidases; D001671:Biochemistry / Q000379:methods; D002268:Carboxypeptidases / Q000737:chemistry / Q000378:metabolism; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009154:Mutation; D009472:Neuronal Ceroid-Lipofuscinoses / Q000378:metabolism; D011480:Protease Inhibitors / Q000737:chemistry; D017434:Protein Structure, Tertiary; D057057:Serine Proteases; D013997:Time Factors; D000091346:Tripeptidyl-Peptidase 1
D011480:Protease Inhibitors; D000091346:Tripeptidyl-Peptidase 1; D002268:Carboxypeptidases; D010450:Endopeptidases; D057057:Serine Proteases; D000626:Aminopeptidases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C000717267:TPP1 protein, human; C479198:sedolisin