RCSB PDB - 5CAC: REFINED STRUCTURE OF HUMAN CARBONIC ANHYDRASE II AT 2.0 ANGSTROMS RESOLUTION (original) (raw)
Refined structure of human carbonic anhydrase II at 2.0 A resolution.
[Eriksson, A.E.](/search?q=citation.rcsb%5Fauthors:Eriksson, A.E.), [Jones, T.A.](/search?q=citation.rcsb%5Fauthors:Jones, T.A.), [Liljas, A.](/search?q=citation.rcsb%5Fauthors:Liljas, A.)
(1988) Proteins 4: 274-282
PubMed: 3151019 Search on PubMed
PubMed Abstract:
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.
Organizational Affiliation:
Department of Molecular Biology, Biomedical Center, Uppsala, Sweden.