Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/1996
Publication Date: N/A
Interpretive Summary: Soybeans accumulate large amounts of oil, a feature that has caused soybeans to emerge as an important agricultural commodity. It would be advantageous to be able to manipulate the amount of oil in soybean seeds, and the research described in this communication is directed toward that goal. The fatty acids, which are a key component of soybean oil, are made in subcellular organelles of plant cells called chloroplasts. The key enzyme that controls the formation of fatty acids is called acetyl CoA carboxylase (ACCase). It is necessary to learn about soybean ACCase to manipulate the oil content of seeds. Soybean biotin carboxyl carrier protein (BCCP), whose DNA coding sequence is described in this communication, is part of ACCase. The DNA sequence information provided in this report will be useful to scientists who want to manipulate soybean oil content.
Technical Abstract: Acetyl CoA carboxylase (EC 184.108.40.206, ACCase) in chloroplasts catalyzes the conversion of acetyl CoA to malonyl CoA, and is a tightly regulated step during the biosynthesis of fatty acids in seeds. In soybeans, ACCase is a multiprotein complex that is considered to consist of 4 subunits: biotin carboxyl carrier protein, biotin carboxylase, and the alpha and beta subunits of carboxyltransferase. In this study, a cDNA clone that encodes BCCP from soybean was described. The clone contained a 1071 bp insert, 786 bp of which were included in an open reading frame. The open reading frame started with an ATG codon at position bp 110 and encoded a 262 amino acid protein that had a high degree of similarity with BCCPs from other sources. The consensus biotinylation motif, (C/G/M)-I-(V/I/L)-G-A-M-K-(M/L)-(M/E)-((N/I), began at position aa239 in soybean BCCP, with the lysine at aa245 the probable site for biotin attachment. The deduced amino acid proprotein contained a typical chloroplast transit sequence at the amino terminal and had a calculated molecular weight of 27,656. The protein contained high proline (14.5%) and alanine (11.4%) contents, and had a calculated isoelectric point at pH 10.2. No potential transmembrane regions were found in the protein which is reportedly associated with thylakoid membranes. Interorganelle sorting analysis predicted the protein to be located in stroma rather than thylakoid membranes.