1QRF:
reference: A closer look at the active site of gamma-class carbonic anhydrases: high-resolution crystallographic studies of the carbonic anhydrase from Methanosarcina thermophila., Iverson TM, Alber BE, Kisker C, Ferry JG, Rees DC, Biochemistry 2000 Aug 8;39(31):9222-31. PMID: 10924115

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