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Publication Abstract from PubMed

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 degrees C, and show that structures of both the Mg(2+) form (KARI:2Mg(2+)) and its ternary complex (KARI:2Mg(2+):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.

Temperature-Resolved Cryo-EM Uncovers Structural Bases of Temperature-Dependent Enzyme Functions.,Chen CY, Chang YC, Lin BL, Huang CH, Tsai MD J Am Chem Soc. 2019 Dec 26;141(51):19983-19987. doi: 10.1021/jacs.9b10687. Epub, 2019 Dec 16. PMID:31829582^[1]

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