Agrocinopine A, a tumor-inducing plasmid-coded enzyme product, is a phosphodiester of sucrose and L-arabinose

• Published in: The Journal of biological chemistry 1984-08, Vol.259 (15), p.9704-9710
• Main Authors: Ryder, M H, Tate, M E, Jones, G P
• Format: Article
• Language: English
• Subjects: Adenine Nucleotides - metabolism; Analytical, structural and metabolic biochemistry; Arabinose - analysis; Biological and medical sciences; Biological Assay; Carbohydrates; Electrophoresis, Polyacrylamide Gel; Fructose - analysis; Fundamental and applied biological sciences. Psychology; Magnetic Resonance Spectroscopy; Other biological molecules; Plants - metabolism; Plasmids; Sugar Phosphates - analysis; Sugar Phosphates - genetics
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(17)42757-8

Opines are unusual compounds found specifically in plant crown gall tumors. Genes for their synthesis and catabolism reside in agrobacteria as tumor-inducing (Ti) plasmid DNA. Only a small Ti-plasmid segment (24 kilobase pairs), the T-DNA, is transferred to the plant cell where it commonly codes for enzymes involved in the biosynthesis of nitrogenous opines such as nopaline (N2-(1,3-D-dicarboxypropyl)-L-arginine) as well as the tumor phenotype. Ellis and Murphy, (Ellis, J.G., and Murphy, P.J. (1981) Mol. Gen. Genet. 181, 36-43) reported the existence of the phosphorylated opines, agrocinopines A and B in tumors containing nopaline. Pure agrocinopine A has now been isolated in a yield of 0.05-0.06 g/100 g, fresh weight, from such tumors. Physical, chemical, and biological data establish the structure of agrocinopine A as an unusual non-nitrogenous opine of sucrose and L-arabinose with a phosphodiester linkage from the 2-hydroxyl of the arabinose to the 4-hydroxyl of the fructose moiety in sucrose. Agrocinopine B is the corresponding phosphodiester, in which the glucose has been hydrolyzed from the sucrose portion of agrocinopine A. Borohydride reduction of the free L-arabinose anomeric carbon of agrocinopine A, to the corresponding arabinitol derivative eliminates the characteristic inhibition zone enhancement produced by both agrocinopines A and B in the agrocin 84 (a fraudulent adenine nucleotide) bioassay. Because of the limited number of genes in the T-DNA, a generalization is proposed, whereby all opines will be found to comprise two common plant cell constituents linked in an uncommon manner by the minimum number of enzymes.