title: ATP binding site in the plant ADP-glucose pyrophosphorylase large subunit.
abstract: The ATP binding region in the catalytically inactive large subunit (LS) of the potato tuber ADP-glucose pyrophosphorylase was identified and investigated. Mutations at the ATP binding significantly affected not only the apparent affinities for ATP and Glc-1-P, and catalytic rate but also in many instances, sensitivity to 3-phosphoglycerate. The catalytic rates of the LS mutant enzymes correlated most strongly with changes in the affinity toward ATP, a relationship substantiated by photoaffinity labeling studies with azido-ATP analog. These results indicate that the LS, although catalytically defective, interacts cooperatively with the catalytic small subunit in binding substrates and effectors and, in turn, influencing net catalysis.
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.
authors.forename: Seon-Kap
authors.initials: SK
authors.lastname: Hwang
authors.forename: Shigeki
authors.initials: S
authors.lastname: Hamada
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Okita
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D001665:Binding Sites; D002384:Catalysis; D051599:Glucose-1-Phosphate Adenylyltransferase / Q000737:chemistry* / Q000378:metabolism*; D005988:Glyceric Acids / Q000378:metabolism; D007700:Kinetics; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D019920:Photoaffinity Labels; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry* / Q000378:metabolism*; D011198:Solanum tuberosum / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D005988:Glyceric Acids; D050505:Mutant Proteins; D019920:Photoaffinity Labels; D021122:Protein Subunits; C005156:3-phosphoglycerate; D000255:Adenosine Triphosphate; D051599:Glucose-1-Phosphate Adenylyltransferase