2RK1:
reference: Crystal structure of a type II dihydrofolate reductase catalytic ternary complex., Krahn JM, Jackson MR, DeRose EF, Howell EE, London RE, Biochemistry. 2007 Dec 25;46(51):14878-88. Epub 2007 Dec 4. PMID: 18052202

This OCA Structure page
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