1ddz
From Proteopedia
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| , resolution 2.2Å | |||||||
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| Ligands: | |||||||
| Activity: | Carbonate dehydratase, with EC number 4.2.1.1 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
X-RAY STRUCTURE OF A BETA-CARBONIC ANHYDRASE FROM THE RED ALGA, PORPHYRIDIUM PURPUREUM R-1
Overview
The carbonic anhydrases (CAs) fall into three evolutionarily distinct families designated alpha-, beta-, and gamma-CAs based on their primary structure. beta-CAs are present in higher plants, algae, and prokaryotes, and are involved in inorganic carbon utilization. Here, we describe the novel x-ray structure of beta-CA from the red alga, Porphyridium purpureum, at 2.2-A resolution using intrinsic zinc multiwavelength anomalous diffraction phasing. The CA monomer is composed of two internally repeating structures, being folded as a pair of fundamentally equivalent motifs of an alpha/beta domain and three projecting alpha-helices. The motif is obviously distinct from that of either alpha- or gamma-CAs. This homodimeric CA appears like a tetramer with a pseudo 222 symmetry. The active site zinc is coordinated by a Cys-Asp-His-Cys tetrad that is strictly conserved among the beta-CAs. No water molecule is found in a zinc-liganding radius, indicating that the zinc-hydroxide mechanism in alpha-CAs, and possibly in gamma-CAs, is not directly applicable to the case in beta-CAs. Zinc coordination environments of the CAs provide an interesting example of the convergent evolution of distinct catalytic sites required for the same CO(2) hydration reaction.
About this Structure
1DDZ is a Single protein structure of sequence from Porphyridium purpureum. The following page contains interesting information on the relation of 1DDZ with [Carbonic Anhydrase]. Full crystallographic information is available from OCA.
Reference
X-ray structure of beta-carbonic anhydrase from the red alga, Porphyridium purpureum, reveals a novel catalytic site for CO(2) hydration., Mitsuhashi S, Mizushima T, Yamashita E, Yamamoto M, Kumasaka T, Moriyama H, Ueki T, Miyachi S, Tsukihara T, J Biol Chem. 2000 Feb 25;275(8):5521-6. PMID:10681531
Page seeded by OCA on Sun Mar 30 19:39:41 2008
