1UGA image
Entry Detail
PDB ID:
1UGA
Title:
HUMAN CARBONIC ANHYDRASE II[HCAII] (E.C.4.2.1.1) MUTANT WITH ALA 65 REPLACED BY PHE (A65F)
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
1996-07-24
Release Date:
1997-01-27
Method Details:
Experimental Method:
Resolution:
2.00 Å
R-Value Free:
0.24
R-Value Work:
0.15
R-Value Observed:
0.15
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:CARBONIC ANHYDRASE II
Mutations:A65F
Chain IDs:A
Chain Length:258
Number of Molecules:1
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
X-ray crystallographic studies of alanine-65 variants of carbonic anhydrase II reveal the structural basis of compromised proton transfer in catalysis.
Biochemistry 35 16429 16434 (1996)
PMID: 8987974 DOI: 10.1021/bi9617872

Abstact

The three-dimensional structures of A65F, A65L, A65H, A65T, A65S, and A65G human carbonic anhydrase II (CAII) variants have been solved by X-ray crystallographic methods to probe the importance of residue 65 and the structural implications of its evolutionary drift in the greater family of carbonic anhydrase isozymes. Structure-activity relationships in this series of CAII variants are correlated with those established for other carbonic anhydrase isozymes. We conclude that a bulky side chain at position 65 hinders the formation of an effective solvent bridge between zinc-bound water and H64 and thereby hinders solvent-mediated proton transfer between these two groups [Jackman, J. E., Merz, K. M., Jr., & Fierke, C. A. (1996) Biochemistry 35, 16421-16428]. Despite the introduction of a polar hydroxyl group at this position, smaller side chains such as serine or threonine substituted for A65 do not perturb the formation of a solvent bridge between H64 and zinc-bound solvent. Thus, the evolution of residue 65 size is one factor affecting the trajectory of catalytic proton transfer.

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Primary Citation of related structures