PDBsum entry 1cay

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Lyase(oxo-acid) PDB id
Protein chain
258 a.a.
Waters ×217

References listed in PDB file
Key reference
Title Wild-Type and e106q mutant carbonic anhydrase complexed with acetate.
Authors K.Håkansson, C.Briand, V.Zaitsev, Y.Xue, A.Liljas.
Ref. Acta Crystallogr D Biol Crystallogr, 1994, 50, 101-104. [DOI no: 10.1107/S0907444993009667]
PubMed id 15299482
Note In the PDB file this reference is annotated as "TO BE PUBLISHED". The citation details given above were identified by an automated search of PubMed on title and author names, giving a perfect match.
The molecular structures of the acetate complexes of wild-type human carbonic anhydrase II (HCAII) and of E106Q mutant human carbonic anhydrase II were solved with high completeness (89-91%) to 2.1 and 1.9 A resolution, respectively. Both wild-type and mutant enzyme crystallize in space group P2(1) with cell dimensions a = 42.7, b = 41.7, c = 73.0 A and beta = 104.6 degrees. The altered active-site hydrogen-bond network caused by the mutation results in a different binding of the inhibitor in the two complexes. In the mutant, but not in the wild-type complex, a carboxylate O atom is within hydrogen-bond distance of Thr199 Ogamma1. In the wild-type enzyme ligand hydrogen bonding to this atom is normally only found for hydrogen-bond donors. The importance of this discrimination on catalysis by the enzyme is discussed briefly.
Figure 1.
Fig. 1. The positions of partially neg- atively charged atoms of some of the carbonic anhydrase-ligand com- plexes. Included are, in addition to the native water molecules 263 and 338 (zinc and deep water), atoms from formate, bisulfite, ni- trate, cyanate, Diamox, aminoben- zolamide as complexed to native human carbonic anhydrase II, and the carboxylate O atoms of bicar- bonate as complexed to cobalt(II)- substituted carbonic anhydrase and to T200H mutant carbonic anhy- drase (l-l~msson, 1992, and refer- ences therein).
The above figure is reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (1994, 50, 101-104) copyright 1994.
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