CLONING AND MOLECULAR ANALYSES OF THE ARABIDOPSIS-THALIANA PLASTID PYRUVATE-DEHYDROGENASE SUBUNITS

Herein we report the first molecular description of the pyruvate dehyd rogenase component of the higher plant plastid pyruvate dehydrogenase complex. The full-length cDNAs for the E1 alpha (1530 bp) and E1 beta (1441 bp) subunits of the Arabidopsis thaliana plastid pyruvate dehydr ogenase contain open reading frames that encode polypeptides of 428 an d 406 amino acids, respectively, with calculated molecular weight valu es of 47120 and 44208. The deduced amino acid sequences for Arabidopsi s plastid E1 alpha and E1 beta have 61% and 68% identity to the odpA a nd odpB genes of the red alga Porphyra purpurea, respectively, but onl y 31% and 32% identity to the plant mitochondrial counterparts. Result s of Southern analyses suggest that each subunit is encoded by a singl e gene, Northern blot analyses indicate expression of mRNAs of the app ropriate size in Arabidopsis leaves. (C) 1997 Elsevier Science B.V.