6KI1

The transmembrane domain of a cyanobacterium bicarbonate transporter BicA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.809 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.227 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structural mechanism of the active bicarbonate transporter from cyanobacteria.

Wang, C.Sun, B.Zhang, X.Huang, X.Zhang, M.Guo, H.Chen, X.Huang, F.Chen, T.Mi, H.Yu, F.Liu, L.N.Zhang, P.

(2019) Nat.Plants 5: 1184-1193

  • DOI: 10.1038/s41477-019-0538-1
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Bicarbonate transporters play essential roles in pH homeostasis in mammals and photosynthesis in aquatic photoautotrophs. A number of bicarbonate transporters have been characterized, among which is BicA-a low-affinity, high-flux SLC26-family bicarbo ...

    Bicarbonate transporters play essential roles in pH homeostasis in mammals and photosynthesis in aquatic photoautotrophs. A number of bicarbonate transporters have been characterized, among which is BicA-a low-affinity, high-flux SLC26-family bicarbonate transporter involved in cyanobacterial CO 2 -concentrating mechanisms (CCMs) that accumulate CO 2 and improve photosynthetic carbon fixation. Here, we report the three-dimensional structure of BicA from Synechocystis sp. PCC6803. Crystal structures of the transmembrane domain (BicA TM ) and the cytoplasmic STAS domain (BicA STAS ) of BicA were solved. BicA TM was captured in an inward-facing HCO 3 - -bound conformation and adopts a '7+7' fold monomer. HCO 3 - binds to a cytoplasm-facing hydrophilic pocket within the membrane. BicA STAS is assembled as a compact homodimer structure and is required for the dimerization of BicA. The dimeric structure of BicA was further analysed using cryo-electron microscopy and physiological analysis of the full-length BicA, and may represent the physiological unit of SLC26-family transporters. Comparing the BicA TM structure with the outward-facing transmembrane domain structures of other bicarbonate transporters suggests an elevator transport mechanism that is applicable to the SLC26/4 family of sodium-dependent bicarbonate transporters. This study advances our knowledge of the structures and functions of cyanobacterial bicarbonate transporters, and will inform strategies for bioengineering functional BicA in heterologous organisms to increase assimilation of CO 2 .


    Organizational Affiliation

    University of Chinese Academy of Sciences, Beijing, China.,Shanghai Key Laboratory of Plant Molecualr Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China.,Institute of Integrative Biology, University of Liverpool, Liverpool, UK.,Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China.,National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China. pengzhang01@sibs.ac.cn.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Low affinity sulfate transporter
A, B
392Synechocystis sp. (strain PCC 6803 / Kazusa)Mutation(s): 0 
Find proteins for Q55415 (Synechocystis sp. (strain PCC 6803 / Kazusa))
Go to UniProtKB:  Q55415
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
OLC
Query on OLC

Download SDF File 
Download CCD File 
A, B
(2R)-2,3-dihydroxypropyl (9Z)-octadec-9-enoate
1-Oleoyl-R-glycerol
C21 H40 O4
RZRNAYUHWVFMIP-GDCKJWNLSA-N
 Ligand Interaction
NA
Query on NA

Download SDF File 
Download CCD File 
A, B
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
BCT
Query on BCT

Download SDF File 
Download CCD File 
A, B
BICARBONATE ION
C H O3
BVKZGUZCCUSVTD-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.809 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.227 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 51.813α = 90.00
b = 103.346β = 95.40
c = 81.521γ = 90.00
Software Package:
Software NamePurpose
HKL-3000data scaling
PDB_EXTRACTdata extraction
PHENIXphasing
PHENIXrefinement
HKL-3000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data

  • Deposited Date: 2019-07-17 
  • Released Date: 2019-11-20 
  • Deposition Author(s): Zhang, P., Wang, C.C.

Funding OrganizationLocationGrant Number
National Natural Science Foundation of ChinaChina31861130356
Chinese Academy of SciencesChinaXDB27020103
Chinese Academy of SciencesChinaQYZDB-SSW-SMC006

Revision History 

  • Version 1.0: 2019-11-20
    Type: Initial release
  • Version 1.1: 2019-12-25
    Type: Database references