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A comparative study of the evolution of cellobiose utilization in Escherichia coli and Shigella sonnei

Joseph, Asha Mary and Sonowal, Robert and Mahadevan, Subramony (2017) A comparative study of the evolution of cellobiose utilization in Escherichia coli and Shigella sonnei. In: ARCHIVES OF MICROBIOLOGY, 199 (2). pp. 247-257.

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Official URL: http://dx.doi.org/10.1007/s00203-016-1299-0


The chb operon of Escherichia coli is involved in the utilization of chitooligosaccharides. While acquisition of two classes of mutations leading to altered regulation of the chb operon is necessary to confer the ability to utilize the glucose disaccharide cellobiose to wild-type strains of E. coli, in the closely related organism Shigella sonnei, Cel(+) mutants arise relatively faster, requiring only a single mutational event. In Type I mutants, the insertion of IS600 at -21 leads to ChbR regulator-independent, constitutive expression of the operon. In Type II mutants, the insertion of IS2/600 within the distal binding site of the negative regulator NagC leads to ChbR-dependent cellobiose-inducible expression of the operon. These studies underscore the significance of strain background, specifically the diversity of transposable elements, in the evolution of novel metabolic functions. Constitutive expression of the chb operon also enables utilization of the aromatic beta-glucosides arbutin and salicin, implying that the chb structural genes are inherently promiscuous.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the SPRINGER, 233 SPRING ST, NEW YORK, NY 10013 USA
Department/Centre: Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Depositing User: Id for Latest eprints
Date Deposited: 03 Apr 2017 04:17
Last Modified: 03 Apr 2017 04:17
URI: http://eprints.iisc.ac.in/id/eprint/56422

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