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dc.contributor.advisorSylte, Ingebrigt
dc.contributor.authorYimingjiang, Wuxiuer
dc.date.accessioned2012-08-29T10:45:32Z
dc.date.available2012-08-29T10:45:32Z
dc.date.issued2012-09-18
dc.description.abstractOriginating from a fruit fly species, Drosophilid alcohol dehydrogenases enzymes (DADHs) belong to the Short-chain dehydrogenases/reductases (SDR) family. Covering a wide range of species, SDR family members show very similar structure and chemical reaction mechanism. In human there are, so fare, at least 24 SDR enzymes that are connected to diseases. Therefore, understanding the function and chemical reaction mechanism of SDR is medically very important. Scaptodrosophilid lebanonensis alcohol dehydrogenase (SlADH) is one of the DADHs of the SDR family. Therefore, it can be used as a model enzyme to study other human disease-related SDR enzymes. SlADH oxidizes alcohol by using the cofactor NAD+. The oxidization reaction consists of proton release and hydride transfer steps. Our study showed that the replacement of the amino acid Threonine with Valine at position 114 in SlADH results in a break of an eight membered chain of water moleculs mediating transport of a proton inside SlADH. Although several enzyme kinetic parameters differ, this mutant follows the same reaction mechanism as the wild type SlADH. For example, the mutation results in a slower hydride transfer from alcohol to NAD+, and slower and weaker binding of NAD+ to the mutant enzyme. Hence, an intact water chain in SlADH is essential for optimal enzyme activity. Other factors may also contribute to these changes, such as the change of dynamical behavior of this enzyme due to the mutation and the broken water chain. A computer based quantum mechanics and molecular mechanics (QM/MM) study of the oxidation mechanism showed that during the alcohol oxidation, the hydride transfer most likely starts first and initiate the proton transfer, and when the proton transfer is finished, the hydride transfer continues until it is finished. Although the QM/MM study gives complementary explanations to the reaction order of these two steps, due to its limitation, more studies are necessary in order to gain more insights into the reaction mechanism of SlADH.en
dc.description.doctoraltypeph.d.en
dc.description.popularabstractWater molecules are essential for full enzyme activity A chain of eight water molecules is essential for full activity of the enzyme Scaptodrosophila lebanonensis alcohol dehydrogenase (SlADH) which belongs to the short-chain alcohol dehydrogenases/reductase family (SDR-family) of enzymes. The title of the doctoral thesis submitted for the Philosophiae Doctor degree is “Structure and function of Scaptodrosophila lebanonensis alcohol dehydrogenase”. In human, at least 24 enzymes of the SDR family have been connected to diseases. Therefore, understanding the function and chemical reaction mechanism of enzymes of the SDR-family is medically very important. SlADH is a member of the SDR-family, and can be used as a model enzyme to study other human disease-related SDR enzymes. In the present study enzyme kinetic studies and molecular modeling studies were used to study the structure and function of SlADH. Our study showed that the replacement of the amino acid Threonine with Valine at position 114 in SlADH results in a break of an eight membered chain of water molecules mediating transport of a proton from the inside of SlADH out to the solvent. SlADH oxidizes alcohols by using NAD+ as cofactor. The oxidization reaction consists of proton release and hydride transfer steps. The mutation resulted in: (1) A slower hydride transfer. (2) Slower and weaker binding of NAD+. (3) Altered molecular motion of the enzyme. A computer based study of the oxidation reaction showed that during the alcohol oxidation, the hydride transfer most likely starts first and initiate the proton transfer, and when the proton transfer is finished, the hydride transfer continues until it is finished. Yimingjiang Wuxiuer was born January 29th, 1979 in Urumqi, China. He received a bachelor’s degree in Medicine at Xi’an Jiaotong University, China (1998-2003). Then he worked in Orthopedic department of Xinjiang Medical University First Hospital (2003-2004). From 2005 to 2006, he worked at International SOS Company, Beijing branch as remote medical officer. He received a master degree at the University of Tromsø in 2008. Since then he has been working as a PhD-student at the Department Medical Biology, University of Tromsø Contact information Name: Yimingjiang Wuxiuer, Institution: Department of Medical Biology, Faculty of Health Sciences, University of Tromsø Phone: 94297885 e-mail: Yimingjiang.wuxiuer@uit.noen
dc.description.sponsorshipthe Norwegian Cancer Society and the University of Tromsøen
dc.descriptionThe papers of this thesis are not available in Munin: <br/>1. Yimingjiang Wuxiuer, Ekaterina Morgunova, Neus Cols, Alexander Popov, Andrey Karshikoff, Ingebrigt Sylte, Roser Gonzàlez-Duarte, Rudolf Ladenstein and Jan-Olof Winberg: 'An intact eight-membered water chain in drosophilid alcohol dehydrogenases is essential for optimal enzyme activity', FEBS Journal (2012), vol.279 no.16:2940–2956. Available at <a href=http://dx.doi.org/10.1111/j.1742-4658.2012.08675.x>http://dx.doi.org/10.1111/j.1742-4658.2012.08675.x</a> <br/>2. Yimingjang Wuxiuer, Jan-Olof Winberg and Ingebrigt Sylte: 'Comparative molecular dynamic simulations of wild type and Thr114Val mutated Scaptodrosophila lebanonensis alcohol dehydrogenase' (manuscript). <br/>3. Yimingjang Wuxiuer, Jan-Olof Winberg and Ingebrigt Sylte: 'QM/MM studies of the catalytic mechanism of short chain alcohol dehydrogenases' (manuscript)en
dc.identifier.urihttps://hdl.handle.net/10037/4393
dc.identifier.urnURN:NBN:no-uit_munin_4111
dc.language.isoengen
dc.rights.accessRightsopenAccess
dc.rights.holderCopyright 2012 The Author(s)
dc.rights.urihttps://creativecommons.org/licenses/by-nc-sa/3.0en_US
dc.rightsAttribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0)en_US
dc.subjectVDP::Medical disciplines: 700::Basic medical, dental and veterinary science disciplines: 710::Medical molecular biology: 711en
dc.subjectVDP::Medisinske Fag: 700::Basale medisinske, odontologiske og veterinærmedisinske fag: 710::Medisinsk molekylærbiologi: 711en
dc.subjectVDP::Medical disciplines: 700::Basic medical, dental and veterinary science disciplines: 710::Pharmacology: 728en
dc.subjectVDP::Medisinske Fag: 700::Basale medisinske, odontologiske og veterinærmedisinske fag: 710::Farmakologi: 728en
dc.titleStructure and function of Scaptodrosophila lebanonensis alcohol dehydrogenaseen
dc.typeDoctoral thesisen
dc.typeDoktorgradsavhandlingen


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