1YQN:
reference: A double mutation of Escherichia coli2C-methyl-D-erythritol-2,4-cyclodiphosphate synthase disrupts six hydrogen bonds with, yet fails to prevent binding of, an isoprenoid diphosphate., Sgraja T, Kemp LE, Ramsden N, Hunter WN, Acta Crystallograph Sect F Struct Biol Cryst Commun. 2005 Jul 1;61(Pt, 7):625-9. Epub 2005 Jun 30. PMID: 16511114

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