5A91:
reference: Exploring the Mechanism of beta-Lactam Ring Protonation in the Class A beta-lactamase Acylation Mechanism Using Neutron and X-ray Crystallography., Vandavasi VG, Weiss KL, Cooper JB, Erskine PT, Tomanicek SJ, Ostermann A, Schrader TE, Ginell SL, Coates L, J Med Chem. 2015 Dec 2. PMID: 26630115

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