PDBsum entry 4cac

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Lyase(oxo-acid) PDB id
Protein chain
256 a.a.
Waters ×160

References listed in PDB file
Key reference
Title Refined structure of human carbonic anhydrase ii at 2.0 a resolution.
Authors A.E.Eriksson, T.A.Jones, A.Liljas.
Ref. Proteins, 1988, 4, 274-282.
PubMed id 3151019
The structure of human erythrocytic carbonic anhydrase II has been refined by constrained and restrained structure-factor least-squares refinement at 2.0 A resolution. The conventional crystallographic R value is 17.3%. Of 167 solvent molecules associated with the protein, four are buried and stabilize secondary structure elements. The zinc ion is ligated to three histidyl residues and one water molecule in a nearly tetrahedral geometry. In addition to the zinc-bound water, seven more water molecules are identified in the active site. Assuming that Glu-106 is deprotonated at pH 8.5, some of the hydrogen bond donor-acceptor relations in the active site can be assigned and are described here in detail. The O gamma 1 atom of Thr-199 donates its proton to the O epsilon 1 atom of Glu-106 and can function as a hydrogen bond acceptor only in additional hydrogen bonds.
Secondary reference #1
Title Crystallographic studies of inhibitor binding sites in human carbonic anhydrase ii: a pentacoordinated binding of the scn- Ion to the zinc at high ph.
Authors A.E.Eriksson, P.M.Kylsten, T.A.Jones, A.Liljas.
Ref. Proteins, 1988, 4, 283-293.
PubMed id 3151020
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