000 02675nab a22004457a 4500
001 G73825
003 MX-TxCIM
005 20170719110424.0
008 121211b |||p||p||||||| |z||| |
022 0 _a0021-9193
040 _aMX-TxCIM
082 0 4 _a91-103384
100 1 _aRozwadowski, K.L.
245 0 0 _aCholine, oxidase, a catabolic enzyme in Arthrobacter pascens, facilitates adaptation to osmotic stress in Escherichia coli
260 _c1991
340 _aPrinted
500 _areferences US (DNAL 448.3 J82)
520 _aCholine 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
546 _aEnglish
595 _aAC
650 1 0 _aAmines
650 1 0 _aAmino compounds
650 1 0 _aAmmonium compounds
650 1 0 _aBacteria
_91017
650 1 0 _aBiochemical reactions
650 1 0 _aBiogenic amines
650 1 0 _aCell structure
650 1 0 _aChemical reactions
650 1 0 _aChromosomes
650 1 0 _aDiffusion
650 1 0 _aEnzymes
650 1 0 _aNucleus
650 1 0 _aPhysical phenomena
650 1 0 _aquaternary ammonium compounds
650 1 0 _aSoil biology
700 1 _aKhachatourians, G.G.,
_ecoaut.
700 1 _aSelvaraj, G.,
_ecoaut.
773 0 _tJournal of bacteriology (USA). (Jan 1991). v. 173(2) p. 472-478
942 _cJA
999 _c21729
_d21729