Part:BBa_K5052312

SbtA Bicarbonate Transporter

About

SbtA is a low-flux, high-affinity bicarbonate transporter. Like most bicarbonate transporters, it is likely a sodium/bicarbonate symporter. SbtA forms a heterodimer with its regulatory unit SbtB ¹. SbtA expression is induced in cyanobacteria when inorganic carbon sources are limiting. It is one of the two inducible bicarbonate transporters, along with BCT1, which is an ATP-binding cassette (ABC) transporter. By only expressing SbtA without SbtB, it can become a constitutive transporter, like BicA, which belongs to the SLC 26 family.

Overexpression of SbtA has been successfully done in E. coli, and it is the best characterized bicarbonate transporter. We chose the SbtA from Cyanobium sp. PCC 7001 due to its high transport rate ².

As SbtA is a membrane protein, its expression should be controlled. This is especially the case when the regulatory unit SbtB is not expressed in conjunction. There needs to be a balance between cell vitality and bicarbonate intake. We did this under an IPTG-inducible promoter cLac145 (Part: BBa_K5052100).

References

(1) Liu, X.-Y.; Hou, W.-T.; Wang, L.; Li, B.; Chen, Y.; Chen, Y.; Jiang, Y.-L.; Zhou, C.-Z. Structures of Cyanobacterial Bicarbonate Transporter SbtA and Its Complex with PII-like SbtB. Cell Discov 2021, 7 (1), 1–5. doi.org/10.1038/s41421-021-00287-w.

(2) Du, J.; Förster, B.; Rourke, L.; Howitt, S. M.; Price, G. D. Characterisation of Cyanobacterial Bicarbonate Transporters in E. Coli Shows That SbtA Homologs Are Functional in This Heterologous Expression System. PLoS One 2014, 9 (12), e115905. https://doi.org/10.1371/journal.pone.0115905.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 210
  
• 1000
  COMPATIBLE WITH RFC[1000]