|TANG, FUQIANG - LOUISIANA STATE UNIV
|SHIH, DING - LOUISIANA STATE UNIV
|Pepperman Jr, Armand
Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/1998
Publication Date: N/A
Interpretive Summary: Our group is interested in understanding the molecular details of tung oil synthesis. Tung oil is used in many industrial applications because it forms tough resistant coatings once it has dried. The active ingredient in tung oil is a fatty acid called eleostearic acid. In characterizing genes involved in the synthesis of this fatty acid, bonds of protein substrates in the presence of of a protein associated with regulation of protein activity has been identified. This glutathione-like protein is unusual in plants. The tung sequence will provide a useful tool for researchers to explore the function of glutathione in plants. Therefore, this research will have the strongest impact on the scientific community.
Technical Abstract: Glutaredoxin catalyzes the reduction of disulfide bonds of protein substrates in the presence of glutathione. The role of this redox regulation in plants is not well understood. Here we report the sequence of a cDNA isolated from tung (Aleurites fordii) that shows significant homology to glutathione proteins. A cDNA library was constructed from tung nuts actively synthesizing tung oil. The library was screened using degenerate PCR primers based on conserved regions of fatty acid desaturase genes. The cDNA for Tngluta, a tung glutathione sequence, was fortuitously identified during this search. The open reading frame encodes a polypeptide of 104 amino acids with a calculated molecular mass of 11.1 kDa. The tetrapeptide Cys-Pro-Tyr-Cys, which constitutes the active site of glutaredoxin, was conserved in the deduced Tngluta amino acid sequence. Tngluta amino acid sequence showed the greatest homology to glutaredoxin from castor bean (79% identity), Fritillaria agrestis (71% identity), rice (70% identity) and yeast (43% identity). Cloning of the glutaredoxin cDNA will greatly facilitate studies of the function of glutaredoxin in tung seed development.