2i4c
From Proteopedia
(New page: 200px<br /><applet load="2i4c" size="350" color="white" frame="true" align="right" spinBox="true" caption="2i4c, resolution 1.70Å" /> '''Crystal structure of...) |
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==Overview== | ==Overview== | ||
| - | Cyanobacteria, blue-green algae, are the most abundant autotrophs in | + | Cyanobacteria, blue-green algae, are the most abundant autotrophs in aquatic environments and form the base of the food chain by fixing carbon and nitrogen into cellular biomass. To compensate for the low selectivity of Rubisco for CO2 over O2, cyanobacteria have developed highly efficient CO2-concentrating machinery of which the ABC transport system CmpABCD from Synechocystis PCC 6803 is one component. Here, we have described the structure of the bicarbonate-binding protein CmpA in the absence and presence of bicarbonate and carbonic acid. CmpA is highly homologous to the nitrate transport protein NrtA. CmpA binds carbonic acid at the entrance to the ligand-binding pocket, whereas bicarbonate binds in nearly an identical location compared with nitrate binding to NrtA. Unexpectedly, bicarbonate binding is accompanied by a metal ion, identified as Ca2+ via inductively coupled plasma optical emission spectrometry. The binding of bicarbonate and metal appears to be highly cooperative and suggests that CmpA may co-transport bicarbonate and calcium or that calcium acts a cofactor in bicarbonate transport. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Synechocystis sp.]] | [[Category: Synechocystis sp.]] | ||
| - | [[Category: Koropatkin, N | + | [[Category: Koropatkin, N M.]] |
| - | [[Category: Pakrasi, H | + | [[Category: Pakrasi, H B.]] |
| - | [[Category: Smith, T | + | [[Category: Smith, T J.]] |
[[Category: BCT]] | [[Category: BCT]] | ||
[[Category: CA]] | [[Category: CA]] | ||
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[[Category: periplasmic solute-binding protein]] | [[Category: periplasmic solute-binding protein]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:48:53 2008'' |
Revision as of 15:48, 21 February 2008
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Crystal structure of Bicarbonate Transport Protein CmpA from Synechocystis sp. PCC 6803 in complex with bicarbonate and calcium
Overview
Cyanobacteria, blue-green algae, are the most abundant autotrophs in aquatic environments and form the base of the food chain by fixing carbon and nitrogen into cellular biomass. To compensate for the low selectivity of Rubisco for CO2 over O2, cyanobacteria have developed highly efficient CO2-concentrating machinery of which the ABC transport system CmpABCD from Synechocystis PCC 6803 is one component. Here, we have described the structure of the bicarbonate-binding protein CmpA in the absence and presence of bicarbonate and carbonic acid. CmpA is highly homologous to the nitrate transport protein NrtA. CmpA binds carbonic acid at the entrance to the ligand-binding pocket, whereas bicarbonate binds in nearly an identical location compared with nitrate binding to NrtA. Unexpectedly, bicarbonate binding is accompanied by a metal ion, identified as Ca2+ via inductively coupled plasma optical emission spectrometry. The binding of bicarbonate and metal appears to be highly cooperative and suggests that CmpA may co-transport bicarbonate and calcium or that calcium acts a cofactor in bicarbonate transport.
About this Structure
2I4C is a Single protein structure of sequence from Synechocystis sp. with and as ligands. Full crystallographic information is available from OCA.
Reference
The structure of a cyanobacterial bicarbonate transport protein, CmpA., Koropatkin NM, Koppenaal DW, Pakrasi HB, Smith TJ, J Biol Chem. 2007 Jan 26;282(4):2606-14. Epub 2006 Nov 22. PMID:17121816
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