Antibodies against an inter-domain segment of polypeptide chain inhibit active-site coupling in the pyruvate dehydrogenase multienzyme complex.
A synthetic peptide, AAPAAAPAKQEAAAPAPAAKAEAPAAAPAAKA, proved to be an efficient and specific immunogen in rabbits. The amino acid sequence of the peptide is identical to that of the inter-domain region (PEP3) linking the innermost of the three lipoyl domains to the dihydrolipoamide dehydrogenase-binding domain in the dihydrolipoamide acetyltransferase chain of the pyruvate dehydrogenase complex of Escherichia coli. Fab fragments from anti-PEP3 antibodies selectively inhibited active-site coupling in the complex without affecting the individual activities of the three component enzymes, highlighting the role of the inter-domain regions as flexible linkers in catalysis.
Radford
S E
SE
Department of Biochemistry, University of Cambridge, England.
Perham
R N
RN
Ullrich
S J
SJ
Appella
E
E
D000906:Antibodies / Q000276:immunology*; D001665:Binding Sites; D001666:Binding Sites, Antibody; D003432:Cross-Linking Reagents; D010455:Peptides / Q000276:immunology*; D011768:Pyruvate Dehydrogenase Complex / Q000037:antagonists & inhibitors*
D000906:Antibodies; D003432:Cross-Linking Reagents; D010455:Peptides; D011768:Pyruvate Dehydrogenase Complex