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United States Department of Agriculture

Agricultural Research Service

Title: Mitochondrial Pyruvate Dehydrogenase Complex: Investigation of the Unique Dihydrolipoamide Acetyltransferase Subcomplex

Authors
item Broz, A - UNIV OF MISSOURI-COLUMBIA
item Mooney, B - UNIV OF MISSOURI-COLUMBIA
item MIERNYK, JAN
item Randall, D - UNIV OF MISSOURI-COLUMBIA

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 3, 2001
Publication Date: N/A

Technical Abstract: The mitochondrial pyruvate dehydrogenase complex (PDC) is critical in regulating the flux of pyruvate through the Krebs cycle. It consists of three enzymatic components which assemble through noncovalent interactions to form a 8x10**6 Da complex. The dihydrolipoamide acetyltransferase (E2) component forms a 60-mer core-complex to which the other components bind. There are two distinct forms of acetyltransferase, a mono-lipoyl form that is believed to be ubiquitous, and a di-lipoyl form which has only been identified in dicots. Recently, two Arabidopsis thaliana genes encoding the mono-lipoyl E2 were identified. The open-reading frames encoded by these genes are highly homologous to the maize E2 protein sequence (also mono- lipoyl). Both mono-lipoyl cDNA sequences were cloned from A. thaliana by RT-PCR. Upon sequencing these clones, discrepancies were found between the experimental and putative sequence data. The computer algorithm intron/exon ncalling was determined to be incorrect based upon sequencing and fragmentation of RT-PCR products. Both full-length cDNAs have been cloned for expression in bacteria and will also be used in protein translation and mitochondrial import experiments. A comparative investigation of the mono and di-lipoyl forms of E2 in A. thaliana and other dicotyledon plants will yield information about their assembly, regulation, and function, as well as their interactions with the other components of the pyruvate dehydrogenase complex.

Last Modified: 9/10/2014
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