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A chemically modified alpha-amylase with a molten-globule state has entropically driven enhanced thermal stability

Siddiqui, Khawar Sohail, Poljak, Anne, De Francisci, Davide, Guerriero, Gea, Pilak, Oliver, Burg, Dominic, Raftery, Mark J, Parkin, Don M, Trewhella, Jill and Cavicchioli, Ricardo (2010) A chemically modified alpha-amylase with a molten-globule state has entropically driven enhanced thermal stability PEDS: Protein Engineering, Design & Selection, 23, (10), pp. 769-780. (doi:10.1093/protein/gzq051). (PMID:20696745).

Record type: Article

Abstract

The thermostability properties of TAA were investigated by chemically modifying carboxyl groups on the surface of the enzyme with AMEs. The TAA(MOD) exhibited a 200% improvement in starch-hydrolyzing productivity at 60 degrees C. By studying the kinetic, thermodynamic and biophysical properties, we found that TAA(MOD) had formed a thermostable, MG state, in which the unfolding of the tertiary structure preceded that of the secondary structure by at least 20 degrees C. The X-ray crystal structure of TAA(MOD) revealed no new permanent interactions (electrostatic or other) resulting from the modification. By deriving thermodynamic activation parameters of TAA(MOD), we rationalised that thermostabilisation have been caused by a decrease in the entropy of the transition state, rather than being enthalpically driven. Far-UV CD shows that the origin of decreased entropy may have arisen from a higher helical content of TAA(MOD). This study provides new insight into the intriguing properties of an MG state resulting from the chemical modification of TAA

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e-pub ahead of print date: 9 August 2010
Published date: October 2010
Organisations: Molecular and Cellular

Identifiers

Local EPrints ID: 338908
URI: http://eprints.soton.ac.uk/id/eprint/338908
ISSN: 1741-0126
PURE UUID: f54a28ce-fae0-4843-9ade-cf3d5385ff18

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Date deposited: 18 May 2012 13:29
Last modified: 18 Jul 2017 05:56

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Contributors

Author: Khawar Sohail Siddiqui
Author: Anne Poljak
Author: Davide De Francisci
Author: Gea Guerriero
Author: Oliver Pilak
Author: Dominic Burg
Author: Mark J Raftery
Author: Don M Parkin
Author: Jill Trewhella
Author: Ricardo Cavicchioli

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