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1y7w
From Proteopedia
| 1y7w, resolution 1.86Å () | |
|---|---|
| Ligands: | , , |
| Gene: | dCA II (Dunaliella salina) |
| Activity: | Carbonate dehydratase, with EC number 4.2.1.1 |
| Domains: | alpha_CA_prokaryotic_like |
| Resources: | FirstGlance, OCA, PDBsum, RCSB, TOPSAN |
| Coordinates: | save as pdb, mmCIF, xml |
Crystal structure of a halotolerant carbonic anhydrase from Dunaliella salina
Protein molecular adaptation to drastically shifting salinities was studied in dCA II, an alpha-type carbonic anhydrase (EC 4.2.1.1) from the exceptionally salt-tolerant unicellular green alga Dunaliella salina. The salt-inducible, extracellular dCA II is highly salt-tolerant and thus differs from its mesophilic homologs. The crystal structure of dCA II, determined at 1.86-A resolution, is globally similar to other alpha-type carbonic anhydrases except for two extended alpha-helices and an added Na-binding loop. Its unusual electrostatic properties include a uniformly negative surface electrostatic potential of lower magnitude than that observed in the highly acidic halophilic proteins and an exceptionally low positive potential at a site adjoining the catalytic Zn(2+) compared with mesophilic homologs. The halotolerant dCA II also differs from typical halophilic proteins in retaining conformational stability and solubility in low to high salt concentrations. The crucial role of electrostatic features in dCA II halotolerance is strongly supported by the ability to predict the unanticipated halotolerance of the murine CA XIV isozyme, which was confirmed biochemically. A proposal for the functional significance of the halotolerance of CA XIV in the kidney is presented.
Three-dimensional structure of a halotolerant algal carbonic anhydrase predicts halotolerance of a mammalian homolog., Premkumar L, Greenblatt HM, Bageshwar UK, Savchenko T, Gokhman I, Sussman JL, Zamir A, Proc Natl Acad Sci U S A. 2005 May 24;102(21):7493-8. Epub 2005 May 13. PMID:15894606
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
of the dCA II structure. The regions corresponding to conserved regions (CRs, blue), variable regions (VRs, lime), and variable conserved regions (VCRs, red), are positioned on the dCA II structure. The catalytic Zn2+, insertions and deletions in VCRs including L1 (the Zn binding loop), L4 (the Na-binding loop), L5, and two extended α-helices (E and G) are marked. N and C termini are labeled.
About this Structure
Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of a halotolerant algal carbonic anhydrase predicts halotolerance of a mammalian homolog., Premkumar L, Greenblatt HM, Bageshwar UK, Savchenko T, Gokhman I, Sussman JL, Zamir A, Proc Natl Acad Sci U S A. 2005 May 24;102(21):7493-8. Epub 2005 May 13. PMID:15894606
Page seeded by OCA on Mon Oct 20 12:03:43 2008
Categories: Carbonate dehydratase | Bageshwar, U K. | Gokhman, I. | Greenblatt, H M. | ISPC, Israel Structural Proteomics Center. | Premkumar, L. | Savchenko, T. | Sussman, J L. | Zamir, A. | Algal carbonic anhydrase | Alpha-type carbonic anhydrase | Anion tolerance | Dca ii | Dunaliella salina carbonic anhydrase | Haltolerant protein | ISPC | Israel Structural Proteomics Center | Salt tolerant protein | Structural genomic | Zinc enzyme
