6NNR:
reference: Mg2+ binds to the surface of thymidylate synthase and affects hydride transfer at the interior active site., Wang Z, Sapienza PJ, Abeysinghe T, Luzum C, Lee AL, Finer-Moore JS, Stroud RM, Kohen A, J Am Chem Soc. 2013 Apr 23. PMID: 23611499

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