Altering the substrate specificity of Candida rugosa LIP4 by engineering the substrate-binding sites

Li Chiun Lee, Yu Ting Chen, Chih Chung Yen, Teresa Ching Yn Chiang, Shye Jye Tang, Guan-Chiun Lee*, Jei Fu Shaw

*此作品的通信作者

研究成果: 雜誌貢獻期刊論文同行評審

19 引文 斯高帕斯(Scopus)

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.

原文英語
頁(從 - 到)5103-5108
頁數6
期刊Journal of Agricultural and Food Chemistry
55
發行號13
DOIs
出版狀態已發佈 - 2007 六月 27

ASJC Scopus subject areas

  • 農業與生物科學(雜項)
  • 食品科學
  • 化學(雜項)

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