Dynamic Interplay of the Myxobacterial Chaperonins

Most of the sequenced myxobacterial genomes possess duplicated groEL genes: one is in a complete bicistronic groESL operon, while the other(s) are in a groESL operon or stand alone. The two groEL genes are subneofunctionalized in Myxococcus xanthus DK1622, the model strain of myxobacteria. Although alternatively essential for cell survival, groEL1 is required for the developmental process, while groEL2 participates in the predation process and the biosynthesis of secondary metabolite myxovirescin. The divergent functions of GroEL1 and GroEL2 are majorly resulted from the differences of the apical and C-terminal equatorial regions of the two paralogous chaperonins. The stand-alone groEL2 gene still requires groES for functions, and the expression levels of groELs and groES genes could be synergic and self-regulated. There is a complicated dynamic interplay between duplicated GroEL proteins and the single cofactor GroES in M. xanthus.