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<text>to colour the structure by Evolutionary Conservation</text> | <text>to colour the structure by Evolutionary Conservation</text> | ||
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</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/ | </jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1w0m ConSurf]. | ||
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Revision as of 01:56, 9 February 2016
TRIOSEPHOSPHATE ISOMERASE FROM THERMOPROTEUS TENAXTRIOSEPHOSPHATE ISOMERASE FROM THERMOPROTEUS TENAX
Structural highlights
Evolutionary Conservation![]() Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedTriosephophate isomerase (TIM) is a dimeric enzyme in eucarya, bacteria and mesophilic archaea. In hyperthermophilic archaea, however, TIM exists as a tetramer composed of monomers that are about 10% shorter than other eucaryal and bacterial TIM monomers. We report here the crystal structure of TIM from Thermoproteus tenax, a hyperthermophilic archaeon that has an optimum growth temperature of 86 degrees C. The structure was determined from both a hexagonal and an orthorhombic crystal form to resolutions of 2.5A and 2.3A, and refined to R-factors of 19.7% and 21.5%, respectively. In both crystal forms, T.tenax TIM exists as a tetramer of the familiar (betaalpha)(8)-barrel. In solution, however, and unlike other hyperthermophilic TIMs, the T.tenax enzyme exhibits an equilibrium between inactive dimers and active tetramers, which is shifted to the tetramer state through a specific interaction with glycerol-1-phosphate dehydrogenase of T.tenax. This observation is interpreted in physiological terms as a need to reduce the build-up of thermolabile metabolic intermediates that would be susceptible to destruction by heat. A detailed structural comparison with TIMs from organisms with growth optima ranging from 15 degrees C to 100 degrees C emphasizes the importance in hyperthermophilic proteins of the specific location of ionic interactions for thermal stability rather than their numbers, and shows a clear correlation between the reduction of heat-labile, surface-exposed Asn and Gln residues with thermoadaptation. The comparison confirms the increase in charged surface-exposed residues at the expense of polar residues. Structure and function of a regulated archaeal triosephosphate isomerase adapted to high temperature.,Walden H, Taylor GL, Lorentzen E, Pohl E, Lilie H, Schramm A, Knura T, Stubbe K, Tjaden B, Hensel R J Mol Biol. 2004 Sep 17;342(3):861-75. PMID:15342242[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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