The structure of a cyanobacterial bicarbonate transport protein, CmpA

Nicole M. Koropatkin, David W. Koppenaal, Himadri B. Pakrasi, Thomas Smith

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)2606-2614
Number of pages9
JournalJournal of Biological Chemistry
Volume282
Issue number4
DOIs
StatePublished - Jan 26 2007
Externally publishedYes

Fingerprint

Bicarbonates
Carrier Proteins
Cyanobacteria
Carbonic Acid
Nitrates
Metals
Ribulose-Bisphosphate Carboxylase
Synechocystis
Food Chain
Inductively coupled plasma
Biomass
Spectrometry
Machinery
Metal ions
Spectrum Analysis
Nitrogen
Carbon
Ions
Ligands
Calcium

ASJC Scopus subject areas

  • Biochemistry

Cite this

The structure of a cyanobacterial bicarbonate transport protein, CmpA. / Koropatkin, Nicole M.; Koppenaal, David W.; Pakrasi, Himadri B.; Smith, Thomas.

In: Journal of Biological Chemistry, Vol. 282, No. 4, 26.01.2007, p. 2606-2614.

Research output: Contribution to journalArticle

Koropatkin, Nicole M. ; Koppenaal, David W. ; Pakrasi, Himadri B. ; Smith, Thomas. / The structure of a cyanobacterial bicarbonate transport protein, CmpA. In: Journal of Biological Chemistry. 2007 ; Vol. 282, No. 4. pp. 2606-2614.
@article{2b981547f0a84d89b980e1895128f6e3,
title = "The structure of a cyanobacterial bicarbonate transport protein, CmpA",
abstract = "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.",
author = "Koropatkin, {Nicole M.} and Koppenaal, {David W.} and Pakrasi, {Himadri B.} and Thomas Smith",
year = "2007",
month = "1",
day = "26",
doi = "10.1074/jbc.M610222200",
language = "English",
volume = "282",
pages = "2606--2614",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "4",

}

TY - JOUR

T1 - The structure of a cyanobacterial bicarbonate transport protein, CmpA

AU - Koropatkin, Nicole M.

AU - Koppenaal, David W.

AU - Pakrasi, Himadri B.

AU - Smith, Thomas

PY - 2007/1/26

Y1 - 2007/1/26

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=34047266662&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34047266662&partnerID=8YFLogxK

U2 - 10.1074/jbc.M610222200

DO - 10.1074/jbc.M610222200

M3 - Article

VL - 282

SP - 2606

EP - 2614

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 4

ER -