ARS | Publication request: Do maise and wheat chloroplast protein synthesis elongation factor, EF-Tu, protect Rubisco activase from thermal aggregation and inactivation?

Submitted to: American Society of Plant Biologists
Publication Type: Abstract Only
Publication Acceptance Date: August 4, 2006
Publication Date: August 9, 2006
Citation: Momcilovic, I., Fu, J., Bukovnik, U., Deridder, B.P., Salvucci, M.E., Ristic, Z. 2006. Do maise and wheat chloroplast protein synthesis elongation factor, EF-Tu, protect Rubisco activase from thermal aggregation and inactivation?. American Society of Plant Biologists. Abstract # P09035. Available: http://abstracts.aspb.org/pb2006/public/cgi-bin/search.cgi.

Technical Abstract: Maize (Zea mays L.) chloroplast protein synthesis elongation factor, EF-Tu, has been implicated in the development of heat tolerance. The precursor of this protein (pre-EF-Tu) has been shown to display chaperone activity, as it protected heat labile citrate synthase and malate dehydrogenase from thermal aggregation and inactivation [Eur. J. Biochem. (2004) 271: 3684-3692]. In the present study, we tested the chaperone activity of maize recombinant pre-EF-Tu towards recombinant maize and wheat (Triticum aestivum L.) Rubisco activase. In addition, we also tested the possible chaperone activity of native maize and wheat EF-Tu using recombinant activase from maize and wheat as a substrate. The recombinant proteins (pre-EF-Tu and Rubisco activase) were purified from E. coli, and the native EF-Tu was purified from maize/wheat leaf tissue. Chaperone assays were conducted in vitro. The results showed that recombinant maize pre-EF-Tu protected activase from heat-induced aggregation. Preliminary results showed that native EF-Tu also displays chaperone activity towards activase. Wheat EF-Tu, for instance, prevented thermal aggregation of maize activase in a concentration dependent manner. Further studies are in progress to determine whether EF-Tu protects Rubisco activase from thermal inactivation.