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National Chung Hsing University Institutional Repository - NCHUIR > 生命科學院 > 基因體暨生物資訊學研究所 > 依資料類型分類 > 期刊論文 >  Altering the substrate specificity of Candida rugosa LIP4 by engineering the substrate-binding sites

Please use this identifier to cite or link to this item: http://nchuir.lib.nchu.edu.tw/handle/309270000/133538

標題: Altering the substrate specificity of Candida rugosa LIP4 by engineering the substrate-binding sites
作者: Lee, L.C.;Chen, Y.T.;Yen, C.C.;Chiang, T.C.Y.;Tang, S.J.;Lee, G.C.;Shaw, J.F.
關鍵字: Candida rugosa;lipase;saturation mutagenesis;substrate specificity;Pichia pastoris;pichia-pastoris;biochemical-characterization;recombinant expression;saturation mutagenesis;cholesterol esterase;multiple mutagenesis;angstrom resolution;directed evolution;lipases family;gene
日期: 2007
Issue Date: 2012-12-14 10:00:50 (UTC+8)
關連: Journal of Agricultural and Food Chemistry, Volume 55, Issue 13, Page(s) 5103-5108.
摘要: Candida rugosa (formerly Candida cylindracea) lipase (CRL) is an important industrial enzyme that is widely used in biotechnological applications such as the production of fatty acids and the synthesis of various esters. CRL comprises at least seven isozymes (LIP1-LIP7), which share a similar amino acid sequence but with different specificities for substrates. Previously, LIP4 was reported to have higher esterase activity toward long acyl-chain ester and lower lipase activity toward triglycerides. A296 and V344 of LIP4 were predicted to play decisive roles in its substrate specificity. In this study, site-specific saturation mutagenesis has been employed to study the substrate specificity of LIP4. Point mutations were separately introduced into A296 and V344 positions using degenerate primer sets containing 32 codons to generate two libraries of variants. LIP4 variants were heterologously expressed in the yeast Pichia pastoris. A specific plate assay was used to identify lipase-producing P. pastoris clones in a medium containing tributyrin. LIP4 variants with high activity toward short fatty acyl-chain triglyceride (tributyrin) were screened. Specificity analysis and biochemical characterization indicated that the recombinant variants A296I, V344Q, and V344H had properties remarkably different from those of wild-type LIP4. All three variant enzymes had significantly higher specific activities toward tributyrin than LIP4. In addition to short-chain triglyceride, A296I and V344Q also improved hydrolytic activities of triglycerides toward medium- and long-chain triglycerides tested. The results suggested that A296 played an important role in lipase activity and high-temperature dependence of LIP4, whereas it had no effect on the chain-length specificity in lipolytic reaction. The V344 residue had a significant effect on the substrate chain-length specificity of LIP4.
Relation: Journal of Agricultural and Food Chemistry
Appears in Collections:[依資料類型分類] 期刊論文
[依教師分類] 陳玉婷
[依教師分類] 陳玉婷
[依教師分類] 陳玉婷

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