1BSG:
reference: The crystal structure of the beta-lactamase of Streptomyces albus G at 0.3 nm resolution., Dideberg O, Charlier P, Wery JP, Dehottay P, Dusart J, Erpicum T, Frere JM, Ghuysen JM, Biochem J 1987 Aug 1;245(3):911-3. PMID: 3499147

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