5HAI:
reference: Removal of the Side Chain at the Active-Site Serine by a Glycine Substitution Increases the Stability of a Wide Range of Serine beta-Lactamases by Relieving Steric Strain., Stojanoski V, Adamski CJ, Hu L, Mehta SC, Sankaran B, Zwart P, Prasad BV, Palzkill T, Biochemistry. 2016 May 3;55(17):2479-90. doi: 10.1021/acs.biochem.6b00056. Epub, 2016 Apr 22. PMID: 27073009

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