Three GroEL homologues from Rhizobium leguminosarum have distinct in vitro properties.
The GroEL molecular chaperone of Escherichia coli and its cofactor GroES are highly conserved, and are required for the folding of many proteins. Most but not all bacteria express single GroEL and GroES proteins. Rhizobium leguminosarum strain A34 encodes three complete operons encoding homologues to GroEL and GroES. We have used circular dichroism and measurement of ATPase activity to compare the stabilities of these chaperonins after expression in and purification from E. coli. Significant differences in the stabilities of the proteins with respect to denaturant and temperature were found. The proteins also differed in their ability to refold denatured lactate dehydrogenase. This study, the first to compare the properties of three different GroEL homologues from the same organism, shows that despite the high degree of similarity between different homologues, they can display distinct properties in vitro.
George
Roger
R
School of Biosciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
Kelly
Sharon M
SM
Price
Nicholas C
NC
Erbse
Annette
A
Fisher
Mark
M
Lund
Peter A
PA
D000251:Adenosine Triphosphatases / Q000737:chemistry; D049109:Cell Proliferation; D018834:Chaperonin 60 / Q000737:chemistry*; D018833:Chaperonins / Q000737:chemistry; D002942:Circular Dichroism; D004926:Escherichia coli / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000737:chemistry / Q000378:metabolism; D011489:Protein Denaturation; D017510:Protein Folding; D016961:Rhizobium leguminosarum / Q000378:metabolism*; D013696:Temperature
D018834:Chaperonin 60; D007770:L-Lactate Dehydrogenase; D000251:Adenosine Triphosphatases; D018833:Chaperonins