Cloning and characterization of the major groESL operon from a nitrogen-fixing cyanobacterium Anabaena sp. strain L-31.

The major heat-shock-responsive operon groESL has been cloned from the cyanobacterial diazotroph Anabaena. The bicistronic operon harbors an upstream negative regulatory CIRCE element and is transcriptionally activated upon temperature upshift. The deduced amino acid sequence displays strong identity/similarity with other cyanobacterial GroES and GroEL proteins.