3E5M

Crystal structure of the HSCARG Y81A mutant

3E5M の概要

• エントリーDOI: 10.2210/pdb3e5m/pdb
• 関連するPDBエントリー: 2EXX
• 分子名称: NmrA-like family domain-containing protein 1 (1 entity in total)
• 機能のキーワード: rossmann fold, oxidoreductase, polymorphism
• 由来する生物種: Homo sapiens (Human)
• 細胞内の位置: Cytoplasm: Q9HBL8
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 66594.55

構造登録者

Li, Y.,Meng, G.,Dai, X.,Luo, M.,Zheng, X. (登録日: 2008-08-14, 公開日: 2009-05-12, 最終更新日: 2023-11-01)

主引用文献

Dai, X.,Li, Y.,Meng, G.,Yao, S.,Zhao, Y.,Yu, Q.,Zhang, J.,Luo, M.,Zheng, X.
NADPH is an allosteric regulator of HSCARG
J.Mol.Biol., 387:1277-1285, 2009

PubMed Abstract: NADP(H) is an important cofactor that controls many fundamental cellular processes. We have determined the crystal structure of HSCARG, a novel NADPH sensor, and found that it forms an asymmetrical dimer with only one subunit occupied by an NADPH molecule, and the two subunits have dramatically different conformations. To study the role of NADPH in affecting the structure and function of HSCARG, here, we constructed a series of HSCARG mutants to abolish NADPH binding ability. Protein structures of two mutants, R37A and Y81A, were solved by X-ray crystallography. The dimerization of wild-type and mutant HSCARG was studied by dynamic light scattering. Differences between the function of wild-type and mutant HSCARG were also compared. Our results show that binding of NADPH is necessary for HSCARG to form a stable asymmetric dimer. The conformation of the monomeric mutants was similar to that of NADPH-bound Molecule I in wild-type HSCARG, although some conformational changes were found in the NADPH binding site. Furthermore, we also noticed that abolition of NADPH binding ability changes the distribution of HSCARG in the cell and that these mutants without NADPH are more strongly associated with argininosuccinate synthetase as compared with wild-type HSCARG. These data suggest that NADPH functions as an allosteric regulator of the structure and function of HSCARG. In response to the changes in the NADPH/NADP(+) ratio within cells, HSCARG, as a redox sensor, associates and dissociates with NADPH to form a new dynamic equilibrium. This equilibrium, in turn, will tip the dimerization balance of the protein molecule and consequently controls the regulatory function of HSCARG.

PubMed: 19254724
DOI: 10.1016/j.jmb.2009.02.049

実験手法

X-RAY DIFFRACTION (2.7 Å)