Submitted to: Biochemical and Biophysical Research Communications
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/16/2000
Publication Date: 1/19/2000
Citation: Mooney, B.P., David, N.R., Thelen, J.J., Miernyk, J.A., Randall, D.D. 2000. Histidine modifying agents abolish pyruvate dehydrogenase kinase activity. Biochemical and Biophysical Research Communications. V.267(2):500-503. Interpretive Summary: Respiration is the use of energy by living cells to do work. Both growth and reproduction are affected by respiration. As a result, respiration must be carefully controlled or wasted energy would decrease crop yields and reduce agricultural productivity. The control of respiration in plant cells is a subject of ongoing study. A protein that is important in the regulation of respiration was isolated from the model plant, thale cress, and studied. Comparisons were made with a similar protein from animals and microbes in order to predict characteristics that might be important in control of respiration. A method was developed to test these predictions by reaction with specific chemical agents. This information will be important to researchers in their attempts to increase agricultural productivity by altering the control of plant cell respiration, and to other plant scientists who will try to design more efficient crop plants through either classical breeding or biotechnology.
Technical Abstract: Pyruvate dehydrogenase kinase specifically phosphorylates the E1-alpha subunit of the pyruvate dehydrogenase complex. Sequence analysis of cloned pyruvate dehydrogenase kinases led to the proposal that they are mechanistically related to prokaryotic 2-component His-kinases. The reaction mechanism of protein His-kinases involves autophosphorylation of a aspecific His residue followed by phospho-transfer to an Asp residue. Treatment of recombinant Arabidopsis thaliana PDK with the His-directed reagents diethyl pyrocarbonate and dichloro (2,2':6',2"-terpyridine)- platinum (II) dihydrate led to a marked inhibition of autophosphorylation. In addition, diethyl pyrocarbonate treatment abolished the ability of pyruvate dehydrogenase kinase to trans-phosphorylate and inactivate the pyruvate dehydrogenase complex. These results validate the prediction that pyruvate dehydrogenase kinases require His residues for activity.