Tetragonal crystal form of the cyanobacterial bicarbonate-transporter regulator SbtB from Synechocystis sp. PCC 6803

Acta Crystallogr F Struct Biol Commun. 2020 Sep 1;76(Pt 9):438-443. doi: 10.1107/S2053230X20010523. Epub 2020 Aug 19.

Abstract

The PII-like protein SbtB has been identified as a regulator of SbtA, which is one of the key bicarbonate transporters in cyanobacteria. While SbtB from Synechocystis sp. PCC 6803 has previously been shown to be a trimer, a new crystal form is reported here which crystallizes in what is thought to be a non-native tetramer in the crystal, with the C-terminus in an extended conformation. The crystal structure shows the formation of an intermolecular disulfide bond at Cys94 between SbtB monomers, which may stabilize this conformation in the crystal. This motivates the need for future studies to investigate the potential role that the oxidation and reduction of these cysteines may play in the activation and/or function of SbtB.

Keywords: SbtB; Synechocystis; bicarbonate transport; cyanobacteria.

MeSH terms

  • Amino Acid Sequence
  • Anion Transport Proteins / chemistry
  • Anion Transport Proteins / genetics
  • Anion Transport Proteins / metabolism
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bicarbonates / chemistry*
  • Bicarbonates / metabolism
  • Binding Sites
  • Cloning, Molecular
  • Crystallography, X-Ray
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Models, Molecular
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Protein Multimerization
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Synechocystis / chemistry*
  • Synechocystis / metabolism

Substances

  • Anion Transport Proteins
  • Bacterial Proteins
  • Bicarbonates
  • Recombinant Proteins