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首页> 外文期刊>Biotechnology Progress >Microbial beta-Galactosidases of industrial importance: Computational studies on the effects of point mutations on the lactose hydrolysis reaction
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Microbial beta-Galactosidases of industrial importance: Computational studies on the effects of point mutations on the lactose hydrolysis reaction

机译：工业重要性的微生物β-半乳糖苷酶：对点突变对乳糖水解反应影响的计算研究

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Hydrolysis efficiency of beta-galactosidases is affected due to a strong inhibition by galactose, hampering the complete lactose hydrolysis. One alternative to reduce this inhibition is to perform mutations in the enzyme's active site. The aim of this study was to evaluate the effect of point mutations on the active site of different microbial beta-galactosidases, using computational techniques. The enzymes of Aspergillus niger (An beta Gal), Aspergillus oryzae (Ao beta Gal), Bacillus circulans (Bc beta Gal), Bifidobacterium bifidum (Bb beta Gal), and Kluyveromyces lactis (Kl beta Gal) were used. The mutations were carried out in all residues that were up to 4.5 angstrom from the galactose/lactose molecules and binding energy was computed. The mutants Tyr96Ala (An beta Gal), Asn140Ala and Asn199Ala (Ao beta Gal), Arg111Ala and Glu355Ala (Bc beta Gal), Arg122Ala and Phe358Ala (Bb beta Gal), Tyr523Ala, Phe620Ala, and Trp582Ala (Kl beta Gal) had the best results, with higher effect on galactose binding energy and lower effect on lactose affinity. To maximize enzyme reactions by reducing galactose affinity, double mutations were proposed for Bc beta Gal, Bb beta Gal, and Kl beta Gal. The double mutations in Bc beta Gal and Bb beta Gal caused the highest reduction in galactose affinity, while no satisfactory results were observed to Kl beta Gal. Using computational tools, mutants that reduced galactose affinity without significantly affecting lactose binding were proposed. The mutations proposed can be used to reduce the negative feedback process, improving the catalytic characteristics of beta-galactosidases and rendering them promising for industrial applications.
机译：β-半乳糖苷酶的水解效率由于半乳糖的强烈抑制而受到影响，妨碍了完整的乳糖水解。减少这种抑制的一种替代方案是在酶的活性位点进行突变。本研究的目的是使用计算技术评估点突变对不同微生物β-半乳糖苷酶的活性位点的影响。使用Aspergillus尼日尔（β1Al），曲霉（Aoβ1al），芽孢杆菌（Bcβ加仑），双歧杆菌（BbβGal）和Kluyveromyces乳酸（KL Beta Gal）酶的酶。在所有残留物中进行突变，该残留物可从半乳糖/乳糖分子中得到4.5埃，并且计算结合能量。突变体Tyr96Ala（β加仑），Asn140Ala和Asn199Ala（Aoβ11aal），Arg111Ala和Glu355Ala（BC Beta Gal），Arg122Ala和Phe358Ala（BB Beta Gal），Tyr523Ala，PHE620Ala和TRP582Ala（KL Beta Gal）具有最好的结果，对半乳糖结合能量较高，对乳糖亲和力的较低影响。通过降低半乳糖亲和力来最大化酶反应，提出了用于BCβGAL，BBβGAL和KL BETA GAL的双突变。 BCβGAL和BBβGAL中的双突变引起了半乳糖亲和力的最高降低，同时对KL Beta Gal没有观察到令人满意的结果。使用计算工具，提出了减少半乳糖亲和力而不会显着影响乳糖结合的突变体。所提出的突变可用于降低负反馈过程，改善β-半乳糖苷酶的催化特征，并使它们对工业应用有望。

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