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Title: GroE heat shock protein is required for in vivo assembly of recombinant Anabaena ribulose bisphosphate (Ru-P sub 2 ) carboxylase/oxygenase

Conference · · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)
OSTI ID:5377540
;  [1]
  1. Oak Ridge National Lab., TN (United States)

As a prerequisite for site-directed mutagenesis of a L{sub 8}S{sub 8} form of Ru-P{sub 2} carboxylase, the rbc operon from Anabaena 7120 was placed under control of the tac promoter (tac-rbcLrbcS, bla, ori(pMB1), from pFL260) in E. coli MV1190 (recA). Substantial amounts of insoluble large subunit were produced, but not active enzyme, suggesting that the carboxylase was not being correctly assembled in vivo. Coexpression of rbcLrbcS and the operon encoding the GroESL (HSP10, HSP60) complex from a compatible plasmid (tac-groESgroEL, cat, ori(p15A), from pFL261) resulted in high levels of active, soluble enzyme. Supplementation of rich medium with potassium ions, required for GroE complex function in vitro enhanced recovery of active enzyme. Under optimal expression conditions, active Ru-P{sub 2} carboxylase comprised 7-10% of soluble protein. The recombinant carboxylase, purified to homogeneity, was similar to the enzyme purified from the authentic cyanobacterium. Chaperonins are required for assembly of many complex proteins. The stringent requirement of Anabaena carboxylase for elevated levels of E. coli GroE chaperonin for proper assembly suggests that the GroE complex differs from the Anabaena chaperonin complex that is normally involved in the assembly of this L{sub 8}S{sub 8} carboxylase.

DOE Contract Number:
AC05-84OR21400
OSTI ID:
5377540
Report Number(s):
CONF-9104107-; CODEN: FAJOE
Journal Information:
FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Vol. 5:4; Conference: 75. annual meeting of the Federation of American Societies for Experimental Biology (FASEB), Atlanta, GA (United States), 21-25 Apr 1991; ISSN 0892-6638
Country of Publication:
United States
Language:
English