2ewh | pdb_00002ewh

Carboxysome protein CsoS1A from Halothiobacillus neapolitanus

spinqualitylabelsall models 2ewh, resolution 1.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2ewh is a 1 chain structure with sequence from "thiobacillus_x"_parker_and_prisk_1953 "thiobacillus x" parker and prisk 1953. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EDO, TRS Gene: csoS1A ("Thiobacillus X" Parker and Prisk 1953) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [CSOA_HALNC] Involved in the formation of the carboxysome, a polyhedral inclusion where RuBisCO is sequestered. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The carboxysome is a bacterial organelle that functions to enhance the efficiency of CO2 fixation by encapsulating the enzymes ribulose bisphosphate carboxylase/oxygenase (RuBisCO) and carbonic anhydrase. The outer shell of the carboxysome is reminiscent of a viral capsid, being constructed from many copies of a few small proteins. Here we describe the structure of the shell protein CsoS1A from the chemoautotrophic bacterium Halothiobacillus neapolitanus. The CsoS1A protein forms hexameric units that pack tightly together to form a molecular layer, which is perforated by narrow pores. Sulfate ions, soaked into crystals of CsoS1A, are observed in the pores of the molecular layer, supporting the idea that the pores could be the conduit for negatively charged metabolites such as bicarbonate, which must cross the shell. The problem of diffusion across a semiporous protein shell is discussed, with the conclusion that the shell is sufficiently porous to allow adequate transport of small molecules. The molecular layer formed by CsoS1A is similar to the recently observed layers formed by cyanobacterial carboxysome shell proteins. This similarity supports the argument that the layers observed represent the natural structure of the facets of the carboxysome shell. Insights into carboxysome function are provided by comparisons of the carboxysome shell to viral capsids, and a comparison of its pores to the pores of transmembrane protein channels. Structural analysis of CsoS1A and the protein shell of the Halothiobacillus neapolitanus carboxysome.,Tsai Y, Sawaya MR, Cannon GC, Cai F, Williams EB, Heinhorst S, Kerfeld CA, Yeates TO PLoS Biol. 2007 Jun;5(6):e144. PMID:17518518 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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