1Y54:
reference: Crystal structure of BRL 42715, C6-(N1-methyl-1,2,3-triazolylmethylene)penem, in complex with Enterobacter cloacae 908R beta-lactamase: evidence for a stereoselective mechanism from docking studies., Michaux C, Charlier P, Frere JM, Wouters J, J Am Chem Soc 2005 Mar 16;127(10):3262-3. PMID: 15755127

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