PDBsum entry 1v9e

Lyase

PDB id: 1v9e

Contents

Protein chains

259 a.a. *

Metals

_ZN ×2

Waters ×576

* Residue conservation analysis

PDB id:

1v9e

Name:

Lyase

Title:

Crystal structure analysis of bovine carbonic anhydrase ii

Structure:

Carbonic anhydrase ii. Chain: a, b. Synonym: carbonate dehydratase ii, ca-ii. Ec: 4.2.1.1

Source:

Bos taurus. Cattle. Organism_taxid: 9913. Cell: erythrocytes

Resolution:

1.95Å R-factor: 0.270 R-free: 0.298

Authors:

R.Saito,T.Sato,A.Ikai,N.Tanaka

Key ref:

R.Saito et al. (2004). Structure of bovine carbonic anhydrase II at 1.95 A resolution. Acta Crystallogr D Biol Crystallogr, 60, 792-795. PubMed id: 15039588 DOI: 10.1107/S0907444904003166

Date:

26-Jan-04 Release date: 10-Feb-04

Protein chains

P00921  (CAH2_BOVIN) -  Carbonic anhydrase 2 from Bos taurus

Seq: 260 a.a.

Struc: 259 a.a.

Enzyme reactions

• Enzyme class 2: E.C.4.2.1.1 - carbonic anhydrase.
• Reaction: hydrogencarbonate + H⁺ = CO2 + H2O
• Cofactor: Zn(2+)
• Enzyme class 3: E.C.4.2.1.69 - cyanamide hydratase.
• Reaction: urea = cyanamide + H2O

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1107/S0907444904003166

Acta Crystallogr D Biol Crystallogr 60:792-795 (2004)

PubMed id: 15039588

Structure of bovine carbonic anhydrase II at 1.95 A resolution.

R.Saito, T.Sato, A.Ikai, N.Tanaka.

ABSTRACT

Carbonic anhydrase (CA) is a zinc-containing enzyme that catalyzes the reversible hydration of CO2 to HCO3-. In eukaryotes, the enzyme plays a role in various physiological functions, including interconversion between CO2 and HCO3- in intermediary metabolism, facilitated diffusion of CO2, pH homeostasis and ion transport. The structure of bovine carbonic anhydrase II (BCA II) has been determined by molecular replacement and refined to 1.95 A resolution by simulated-annealing and individual B-factor refinement. The final R factor for the BCA II structure was 19.4%. BCA II has a C-terminal knot structure similar to that observed in human CA II. It contains one zinc ion in the active site coordinated to three histidines and one putative water molecule in a tetrahedral geometry. The structure of BCA II reveals a probable alternative proton-wire pathway that differs from that of HCA II.

Selected figure(s)

Figure 2.
Figure 2 Schematic drawing of interactions and distances around the active site determined from the crystal structure of BCA II at pH 7.5. The net charges assigned by theoretical calculations using MOPAC are shown. The side-chain atom Gln91 O 1 (net charge -0.30) accepts a hydrogen bond from of His93 N 1 (net charge -0.21) and contributes to His93 ligand stabilization. The side-chain atom of Gln91 N 2, with a net charge of -0.40, has a dominant role in the binding of water molecule W482, with net charge of +0.02, in its slightly acidic or cationic form. This interaction is likely to be more hydrogen-bonding in character than the interaction between W162 (net charge +0.01) and His63 N 2 (net charge -0.14) that has been a biological focus in the case of HCA II. This finding suggests that the dipole donor group of Gln91 may also participate in processes that require relatively rapid proton movement or release.

The above figure is reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2004, 60, 792-795) copyright 2004.

Figure was selected by an automated process.