The mitochondrial pyruvate dehydrogenase complex: nucleotide and deduced amino-acid sequences of a cDNA encoding the Arabidopsis thaliana E1 α-subunit

A cDNA encoding the Elα subunit of the Arabidopsis thaliana (At) mitochondrial (mt) pyruvate dehydrogenase complex (PDC) was sequenced. The 1435-bp cDNA consists of a 1167-bp open reading frame encoding a 43.0-kDa polypeptide of 389 amino acids (aa) (p I 7.1). The plant Elα subunit has 47–51% aa sequence identity with other eukaryotic sequences. Among the regions that are highly conserved are the aa surrounding phosphorylation sites 1 and 2 of the mammalian sequence, including the conserved Ser 292 residue of At at site 1. An essential active site residue, Cys 62 of the bovine subunit, is also conserved. A 32-aa presumptive mt targeting sequence is present at the N terminus.