1C9K:
reference: Three-dimensional structure of adenosylcobinamide kinase/adenosylcobinamide phosphate guanylyltransferase (CobU) complexed with GMP: evidence for a substrate-induced transferase active site., Thompson TB, Thomas MG, Escalante-Semerena JC, Rayment I, Biochemistry 1999 Oct 5;38(40):12995-3005. PMID: 10529169

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