Knowledge Center Catalog

Choline, oxidase, a catabolic enzyme in Arthrobacter pascens, facilitates adaptation to osmotic stress in Escherichia coli

Rozwadowski, K.L.

Choline, oxidase, a catabolic enzyme in Arthrobacter pascens, facilitates adaptation to osmotic stress in Escherichia coli - 1991 - Printed

references US (DNAL 448.3 J82)

Choline oxidase (EC 1.1.3.17) is a bifunctional enzyme that is capable of catalyzing glycine betaine biosynthesis from choline via betaine aldehyde. A gene (cox) encoding this enzyme in the gram-positive soil bacterium Arthrobacter pascens was isolated and characterized. This gene is contained within a 1.9-kb fragment that encodes a polypeptide of approximately 66 kDa. Transfer of this gene to an Escherichia coli mutant that is defective in betaine biosynthesis resulted in an osmotolerant phenotype. This phenotype was associated with the ability of the host to synthesize and assemble an enzymatically active choline oxidase that could catalyze biosynthesis of glycine betaine from an exogenous supply of choline. Although glycine betaine functions as an osmolyte in several different organisms, it was not found to have this role in A. pascens. Instead, both choline and glycine betaine were utilized as carbon sources. in A. pascens synthesis and activity of choline oxidase were modulated by carbon sources and were susceptible to catabolite repression. Thus, cox, a gene concerned with carbon utilization in A. pascens, was found to play a role in adaptation to an environmental stress in a heterologous organism. In addition to providing a possible means of manipulating osmotolerance in other organisms, the cox gene offers a model system for the study of choline oxidation, an important metabolic process in both procaryotes and eucaryotes


English

0021-9193


Amines
Amino compounds
Ammonium compounds
Bacteria
Biochemical reactions
Biogenic amines
Cell structure
Chemical reactions
Chromosomes
Diffusion
Enzymes
Nucleus
Physical phenomena
quaternary ammonium compounds
Soil biology

91-103384

International Maize and Wheat Improvement Center (CIMMYT) © Copyright 2021.
Carretera México-Veracruz. Km. 45, El Batán, Texcoco, México, C.P. 56237.
If you have any question, please contact us at
CIMMYT-Knowledge-Center@cgiar.org