3b20

Publication Abstract from PubMed

The reversible formation of a glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-CP12-phosphoribulokinase (PRK) supramolecular complex, identified in oxygenic photosynthetic organisms, provides light-dependent Calvin cycle regulation in a coordinated manner. An intrinsically disordered protein (IDP) CP12 acts as a linker to sequentially bind GAPDH and PRK to downregulate both enzymes. Here, we report the crystal structures of the ternary GAPDH-CP12-NAD and binary GAPDH-NAD complexes from Synechococcus elongates. The GAPDH-CP12 complex structure reveals that the oxidized CP12 becomes partially structured upon GAPDH binding. The C-terminus of CP12 is inserted into the active-site region of GAPDH, resulting in competitive inhibition of GAPDH. This study also provides insight into how the GAPDH-CP12 complex is dissociated by a high NADP(H)/NAD(H) ratio. An unexpected increase in negative charge potential that emerged upon CP12 binding highlights the biological function of CP12 in the sequential assembly of the supramolecular complex.

Structure Basis for the Regulation of Glyceraldehyde-3-Phosphate Dehydrogenase Activity via the Intrinsically Disordered Protein CP12.,Matsumura H, Kai A, Maeda T, Tamoi M, Satoh A, Tamura H, Hirose M, Ogawa T, Kizu N, Wadano A, Inoue T, Shigeoka S Structure. 2011 Dec 7;19(12):1846-54. PMID:22153507^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.