PMID:391567

Citation	Cole, ST and Guest, JR (1979) Production of a soluble form of fumarate reductase by multiple gene duplication in Escherichia coli K12.Eur. J. Biochem. 102:65-71
Abstract	1. Ampicillin-hyperresistant mutants of Escherichia coli K12 bearing multiple gene duplications in the ampC (beta-lactamase) gene region of the chromosome overproduced at least six proteins with molecular weights 97,000, 80,000, 72,000, 49,000, 33,000 and 26,500 during anaerobic growth. All but two of the proteins (80,000-Mr and 49,000-Mr) were also overproduced during aerobic growth. The distribution of the proteins in soluble and particulate cell fractions was investigated. 2. The 33,000-Mr and 72,000-Mr components were identified as beta-lactamase and the amp-linked frdA gene product, fumarate reductase, respectively. Co-sedimentation of the 26,500-Mr component with the fumarate reductase suggested that the smaller protein could be functionally related to the reductase. The lack of correspondence between the amplified proteins and the products of other amp-linked genes, aspA and mop(groE), indicated that these genes are not included in the repetitive sequence. 3. Fumarate reductase activities were amplified up to 32-fold by the multiple gene duplications. Two forms of fumarate reductase were produced: particulate (membrane-bound) and soluble (cytoplasmic). Production of the soluble form occurred when the binding capacity of the membrane was saturated. Both forms of fumarate reductase were enzymically active but the soluble form was readily inactivated under assay conditions.
Links	PubMed
Keywords	Centrifugation, Density Gradient; Chromosome Aberrations; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Fumarates; Molecular Weight; Mutation; Oxidoreductases; Solubility; Subcellular Fractions; beta-Lactamases
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Materials and Methods Used

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Phenotype Annotations

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Phenotype of	Taxon Information	Genotype Information (if known)	Condition Information	OMP ID	OMP Term Name	ECO ID	ECO Term Name	Notes	Status
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K12 Substrain: JRG997 NCBI Taxon ID: 83333	Genotype of Reference Strain: ampC + Genotype of Experimental Strain : ampC -	Reference Condition: anaerobic and aerobic growth medium Experimental Condition: anaerobic and aerobic growth medium	OMP:0000267	increased gene expression	ECO:0000046	protein expression level analysis
a mutation or genetic difference within a strain	Taxon: Escherichia coli Strain: K-12 Substrain: NCBI Taxon ID: 83333	Genotype of Reference Strain: ampA Genotype of Experimental Strain : ampA1	Reference Condition:	OMP:0000276	increased resistance to antimicrobial compound	ECO:0000033	traceable author statement	ampicillin resistance. Traceable here
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