6ASI:
reference: Structural Control of Nonnative Ligand Binding in Engineered Mutants of Phosphoenolpyruvate Carboxykinase., Tang HYH, Shin DS, Hura GL, Yang Y, Hu X, Lightstone FC, McGee MD, Padgett HS, Yannone SM, Tainer JA, Biochemistry. 2018 Dec 4;57(48):6688-6700. doi: 10.1021/acs.biochem.8b00963. Epub, 2018 Nov 15. PMID: 30376300

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