Isolation, Characterization And Nucleotide-Sequences Of The Aroc Genes Encoding Chorismate Synthase From Salmonella-Typhi And Escherichia-Coli
- Soc General Microbiology
- Publication Type:
- Journal Article
- Journal Of General Microbiology, 1990, 136 (NA), pp. 353 - 358
- Issue Date:
The aroC genes from Salmoneffa @phi and Escherichia cofi, encoding 5-enolpyruvylshikimate-3-phosphate phospholyase (chorismate synthase) were cloned in E. coli and their DNA sequences were determined. The aroC gene from S @phi was isolated from a cosmid gene bank by complementation of an E. cofi aroC mutant. The corresponding E. coli gene was isolated from a pBR322 gene bank by colony hybridization using DNA encoding the aroC gene from S. @phi as a hybridization probe. Analysis of the nucleotide sequence revealed that both genes have an open reading frame capable of encoding proteins comprising 361 amino acids. The calculated molecular mass of the protein from S fyphi is 39 10s Da while that of the protein from E cofi is 39 138 Da. Homology is particularly strong between the coding regions of the genes: 95% when protein sequences are compared, and 83% when DNA sequences are examined. Use of a deletion variant of the E. cofi aroC gene demonstrates that the C-terminal36 amino acids are not essential for the correct folding or functional activity of the chorismate synthase enzyme.
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