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B6db references: 97420851

type Journal Article
authors Rekoslavskaya, N. I.; Kuznetsova, E. V.; Vysotskaya, E. F.; Salyaev, R. K.
title Tryptophan synthase from Agrobacterium tumefaciens 8628: isolation and properties
journal Biochemistry (Mosc)
ui 97420851
year (1997)
volume 62
number 4
pages 433-9.
keywords Agrobacterium/*enzymology/pathogenicity
abstract Tryptophan synthase was isolated from a highly virulent strain of Agrobacterium tumefaciens 8628 (octopine type). Separation of tryptophan synthase from thermolabile protease was accomplished using fractionation with polyethylene glycol-6000 followed by ion-exchange chromatography with a pH gradient. Molecular weights of alpha- and beta- subunits are 33 and 51 kD, respectively. The tryptophan synthase is stable at 60 degrees C because of heat-tolerance beta-subunits. After heating the activity of tryptophan synthase increased up to 20 times while temperature-labile proteases lost their activities. Reaction with antibodies showed the presence of four protein bands, one of which was coeluted with nucleic acids during ion-exchange chromatography. It is suggested that the basic tryptophan synthase is encoded by trp genes in a plasmid and its role is to provide the precursor with the prokaryotic pathway of indole-3-acetic acid biosynthesis, which determines the virulence of A. tumefaciens. There is perhaps a cooperation between iaaM, iaaH, and trp genes in the plasmid during plant cell transformation.
last changed 2002/11/12 16:17

B6db references