6KPJ

298 K cryoEM structure of Sso-KARI in complex with Mg2+, NADH and CPD

Summary for 6KPJ

• Entry DOI: 10.2210/pdb6kpj/pdb
• Related: 6KOU
• EMDB information: 0748
• Descriptor: Ketol-acid reductoisomerase, MAGNESIUM ION, 1,4-DIHYDRONICOTINAMIDE ADENINE DINUCLEOTIDE, ... (4 entities in total)
• Functional Keywords: complex, isomerase
• Biological source: Saccharolobus solfataricus
• Total number of polymer chains: 12
• Total formula weight: 456888.06

Authors

Chen, C.Y.,Chang, Y.C.,Lin, B.L.,Huang, C.H.,Tsai, M.D. (deposition date: 2019-08-15, release date: 2020-03-25, Last modification date: 2024-03-27)

Primary citation

Chen, C.Y.,Chang, Y.C.,Lin, B.L.,Huang, C.H.,Tsai, M.D.
Temperature-Resolved Cryo-EM Uncovers Structural Bases of Temperature-Dependent Enzyme Functions.
J.Am.Chem.Soc., 141:19983-19987, 2019

PubMed Abstract: Protein functions are temperature-dependent, but protein structures are usually solved at a single (often low) temperature because of limitations on the conditions of crystal growth or protein vitrification. Here we demonstrate the feasibility of solving cryo-EM structures of proteins vitrified at high temperatures, solve 12 structures of an archaeal ketol-acid reductoisomerase (KARI) vitrified at 4-70 °C, and show that structures of both the Mg form (KARI:2Mg) and its ternary complex (KARI:2Mg:NADH:inhibitor) are temperature-dependent in correlation with the temperature dependence of enzyme activity. Furthermore, structural analyses led to dissection of the induced-fit mechanism into ligand-induced and temperature-induced effects and to capture of temperature-resolved intermediates of the temperature-induced conformational change. The results also suggest that it is preferable to solve cryo-EM structures of protein complexes at functional temperatures. These studies should greatly expand the landscapes of protein structure-function relationships and enhance the mechanistic analysis of enzymatic functions.

PubMed: 31829582
DOI: 10.1021/jacs.9b10687

Experimental method

ELECTRON MICROSCOPY (2.56 Å)