Negative Cooperativity and High Affinity in Chitooligosaccharide Binding by a Mycobacterium smegmatis Protein Containing LysM and Lectin Domains

Patra, Dhabaleswar and Mishra, Padmanabh and Vijayan, Mamannamana and Surolia, Avadhesha (2016) Negative Cooperativity and High Affinity in Chitooligosaccharide Binding by a Mycobacterium smegmatis Protein Containing LysM and Lectin Domains. In: BIOCHEMISTRY, 55 (1). pp. 49-61.

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Abstract

LysM domains have been recognized in bacteria and eukaryotes as carbohydrate-binding protein modules, but the mechanism of their binding to chitooligosaccharides has been underexplored. Binding of a Mycobacterium smegmatis protein containing a lectin (MSL) and one LysM domain to chitooligosaccharides has been studied using isothermal titration calorimetry and fluorescence titration that demonstrate the presence of two binding sites of nonidentical affinities per dimeric MSL-LysM molecule. The affinity of the molecule for chitooligosaccharides correlates with the length of the carbohydrate chain. Its binding to chitooligosaccharides is characterized by negative cooperativity in the interactions of the two domains. Apparently, the flexibility of the long linker that connects the LysM and MSL domains plays a facilitating role in this recognition. The LysM domain in the MSL-LysM molecule, like other bacterial domains but unlike plant LysM domains, recognizes equally well peptidoglycan fragments as well as chitin polymers. Interestingly, in the case presented here, two LysM domains are enough for binding to peptidoglycan in contrast to the three reportedly required by the LysM domains of Bacillus subtilis and Lactococcus lactis. Also, the affinity of the MSL-LysM molecule for chitooligosaccharides is higher than that of LysM-chitooligosaccharide interactions reported so far.

Item Type:	Journal Article
Publication:	BIOCHEMISTRY
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	17 Feb 2016 07:50
Last Modified:	17 Feb 2016 07:50
URI:	http://eprints.iisc.ac.in/id/eprint/53273

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