title: A catalytic site of protein disulfide isomerase probed with adenosine-5'-triphosphate analogs.
abstract: Anthraniloyl adenosine-5'-triphosphate (Ant-ATP) and etheno-adenosine-5'-triphosphate (epsilon-ATP) complexed to Mg(2+) ions are substrates of protein disulfide isomerase (PDI). epsilon-ATP, coordinated to Tb(3+) ions, was used as a probe of the ATPase binding site. Sensitized luminescence arising from resonance energy transfer from epsilon-adenine to Tb(3+) is quenched by PDI. The luminescence results are discussed in reference to a model in which the distance of separation between epsilon-adenine (donor) and Tb(3+) (acceptor) is increased upon binding of PDI. The interaction of a small peptide of 14 amino acid residues with the b/b' domain of the protein does not influence the ATPase activity. The phosphorescence, fluorescence and fluorescence anisotropy of bound epsilon-ATP are not perturbed by the binding of the small molecular weight peptide to PDI. It is suggested that the peptide and ATP do not share a common binding site on the b/b' domain.
authors.affiliation: Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hong Kong, PR China.
authors.forename: J E
authors.initials: JE
authors.lastname: Churchich
authors.forename: K S
authors.initials: KS
authors.lastname: Lee
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000737:chemistry; D000818:Animals; D020134:Catalytic Domain; D005454:Fluorescence Polarization; D036341:Intercellular Signaling Peptides and Proteins; D015335:Molecular Probes; D010455:Peptides; D011485:Protein Binding; D019704:Protein Disulfide-Isomerases / Q000737:chemistry / Q000378:metabolism*; D013552:Swine; D014862:Wasp Venoms / Q000378:metabolism
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D015335:Molecular Probes; D010455:Peptides; D014862:Wasp Venoms; C037500:mastoparan; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D019704:Protein Disulfide-Isomerases