通过随机诱变提高海洋粘球菌来源重组β-琼胶酶 AgaB 的热稳定性。
Enhancement of the thermostability of a recombinant beta-agarase, AgaB, from Zobellia galactanivorans by random mutagenesis.
机构信息
Department of Pharmaceutical Engineering, College of Medical Life Sciences, Silla University, Busan, 617-736, Korea.
出版信息
Biotechnol Lett. 2010 Jul;32(7):943-9. doi: 10.1007/s10529-010-0237-5. Epub 2010 Mar 8.
Random mutagenesis was performed on beta-agarase, AgaB, from Zobellia galactanivorans to improve its catalytic activity and thermostability. The activities of three mutants E99K, T307I and E99K-T307I were approx. 140, 190 and 200%, respectively, of wild type beta-agarase (661 U/mg) at 40 degrees C. All three mutant enzymes were stable up to 50 degrees C and E99K-T307I had the highest thermostability. The melting temperature (Tm) of E99K-T307I, determined by CD spectra, was increased by 5.2 degrees C over that of the wild-type enzyme (54.6 degrees C). Activities of both the wild-type and E99K-T307I enzymes, as well as their overall thermostabilities, increased in 1 mM CaCl2. The E99K-T307I enzyme was stable at 55 degrees C with 1 mM CaCl2, reaching 260% of the activity the wild-type enzyme held at 40 degrees C without CaCl2.
对来自泽氏寡养单胞菌的β-琼脂酶（AgaB）进行随机诱变，以提高其催化活性和热稳定性。三个突变体 E99K、T307I 和 E99K-T307I 的活性在 40°C 时分别约为野生型β-琼脂酶（661 U/mg）的 140%、190%和 200%。所有三种突变酶在高达 50°C 时都稳定，而 E99K-T307I 具有最高的热稳定性。通过 CD 光谱测定，E99K-T307I 的熔点（Tm）比野生型酶升高了 5.2°C（54.6°C）。野生型和 E99K-T307I 酶的活性以及它们的整体热稳定性均在 1 mM CaCl2 中增加。E99K-T307I 酶在 55°C 时在 1 mM CaCl2 下稳定，达到在没有 CaCl2 的情况下 40°C 时野生型酶活性的 260%。
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