Thirty-degree shift in optimum temperature of a thermophilic lipase by a single-point mutation: effect of serine to threonine mutation on structural flexibility

Sharma, Monika and Kumar, Rakesh and Singh, Ranvir and Kaur, Jagdeep (2017) Thirty-degree shift in optimum temperature of a thermophilic lipase by a single-point mutation: effect of serine to threonine mutation on structural flexibility. In: MOLECULAR AND CELLULAR BIOCHEMISTRY, 430 (1-2). pp. 21-30.

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Abstract

In order to understand the molecular basis of cold adaptation, we have used directed evolution to transform a thermophilic lipase LipR1 into its psychrophilic counterpart. A single round of random mutagenesis followed by screening for improved variants yielded a mutant with single-point mutation LipR1M1 (S130T), with optimum activity at 20 degrees C. Its activity at 50 degrees C is only 20% as compared to wild type (100%). It showed catalytic rate constant (k(cat)) 3 times higher and a catalytic efficiency (k(cat)/K-m) 4 times that of wild type. Circular dichroism and fluorescence studies also supported our observation of mutant structural flexibility. Structure analysis using homology models showed that Threonine 130 is exposed to solvent and has lost H-bond interaction with neighboring amino acid, thereby increasing flexibility of this lipase structure.

Item Type:	Journal Article
Publication:	MOLECULAR AND CELLULAR BIOCHEMISTRY
Additional Information:	Copy right for this article belongs to the SPRINGER, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	10 Jun 2017 04:37
Last Modified:	10 Jun 2017 04:37
URI:	http://eprints.iisc.ac.in/id/eprint/57141

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