Department of Biotechnology, Pukyong National University, Busan, 48513, Republic of Korea.
Industrial Bio-Materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Republic of Korea.
Enzyme Microb Technol. 2019 Jul;126:69-76. doi: 10.1016/j.enzmictec.2019.04.002. Epub 2019 Apr 3.
The beta-propeller phytase (BPP) is an enzyme that hydrolyzes phyate to release inorganic phosphorus. The BPP produced by Pseudomonas sp. FB15 (PSphy) possesses an additional N-terminal domain that is not present in BPP produced by other Bacillus species. In this study, BPP produced by Bacillus sp. SJ-10 (SJ-10phy) was fused with the N-terminal domain of PSphy and the enzymatic properties of the resulting fusion protein (FUSJ-10phy) were investigated. FUSJ-10phy exhibited an optimal temperature that was 10 °C lower than that of the wild-type enzyme. A comparison of kinetic parameters showed that the turnover rate of FUSJ-10phy was 2.39-fold higher than that of SJ-10phy, representing a 1.79-fold increase in catalytic efficiency. In addition, BPP produced by Bacillus sp. SJ-48 has relatively low sequence similarity with SJ-10phy, was fused with N-terminal domain (FUSJ-48phy). FUSJ-48phy also increased catalytic efficiency and changed the optimal temperature. These results indicate that, when fused to other BPPs, the N-terminal domain of PSphy increases catalytic efficiency and enzyme activity at lower temperatures.
β-折叠植酸酶（BPP）是一种能够将植酸水解为无机磷的酶。假单胞菌 FB15（PSphy）产生的 BPP 具有一个额外的 N 端结构域，而其他芽孢杆菌产生的 BPP 则没有这个结构域。在本研究中，将芽孢杆菌 SJ-10（SJ-10phy）产生的 BPP 与 PSphy 的 N 端结构域融合，并研究了所得融合蛋白（FUSJ-10phy）的酶学性质。FUSJ-10phy 的最适温度比野生型酶低 10°C。动力学参数比较表明，FUSJ-10phy 的转换率比 SJ-10phy 高 2.39 倍，表明其催化效率提高了 1.79 倍。此外，与 SJ-10phy 具有相对较低序列相似性的芽孢杆菌 SJ-48 产生的 BPP 与 N 端结构域融合（FUSJ-48phy）。FUSJ-48phy 也提高了催化效率并改变了最适温度。这些结果表明，当与其他 BPP 融合时，PSphy 的 N 端结构域可提高催化效率和在较低温度下的酶活性。
