research communications
The CO2-concentrating mechanism (CCM) has evolved to improve the efficiency of photosynthesis in autotrophic cyanobacteria. CmpR, a LysR-type transcriptional regulator (LTTR) from Synechococcus elongatus PCC 7942, was found to regulate CCM-related genes under low-CO2 conditions. Here, the dimeric structure of the effector-binding domain of CmpR (CmpR-EBD) in complex with the co-activator ribulose 1,5-bisphosphate (RuBP) is reported at 2.15 Å resolution. One RuBP molecule binds to the inter-domain cleft between the two subunits of the CmpR-EBD dimer. Structural comparison combined with sequence analyses demonstrated that CmpR-EBD has an overall structure similar to those of LTTRs of known structure, but possesses a distinctly different effector-binding pattern.
Keywords: crystal structure; LysR-type transcription factors; cyanobacteria; Synechococcus elongatus PCC 7942; CmpR-EBD complex with ribulose 1,5-bisphosphate; CO2-concentrating mechanism.
Supporting information
PDB reference: CmpR effector-binding domain, complex with ribulose 1-5-bisphosphate, 5z49