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ATP binding site in the plant ADP‐glucose pyrophosphorylase large subunit
Author(s) -
Hwang Seon-Kap,
Hamada Shigeki,
Okita Thomas W.
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.11.029
Subject(s) - protein subunit , allosteric regulation , biochemistry , enzyme , chemistry , photoaffinity labeling , binding site , mutant , atp synthase , catalysis , gene
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.