Department of Molecular Science and Technology, Graduate School of Interdisciplinary Programs, Ajou University, Suwon 443-749, South Korea.
Int J Biol Macromol. 2010 Mar 1;46(2):145-52. doi: 10.1016/j.ijbiomac.2009.12.010. Epub 2010 Jan 8.
A novel oligomeric SGNH-arylesterase (Sm23) from Sinorhizobium meliloti 1021 was characterized using biochemical and biophysical methods. A sequence comparison of Sm23 with other SGNH members confirmed the presence of catalytic triad (Ser(10), Asp(187), and His(190)) and oxyanion holes (Ser(10)-Gly(50)-Asn(90)). The wild type enzyme was able to hydrolyze p-nitrophenyl acetate, alpha- and beta-naphthyl acetate, while S10A mutant completely lost its activity. Structural properties of Sm23 were investigated using circular dichroism (CD), fluorescence, dynamic light scattering (DLS), chemical cross-linking, electron microscopy (EM), and time of flight (TOF) mass spectrometry. Furthermore, spherical or globular aggregates were observed with 1-butyl-3-methylimidazolium tetrafluoroborate, while amorphous aggregates were formed with 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.
一种新型寡聚 SGNH-芳酯酶（Sm23）来自苜蓿中华根瘤菌 1021，采用生化和生物物理方法进行了表征。Sm23 与其他 SGNH 成员的序列比较证实了催化三联体（Ser(10)、Asp(187)和 His(190))和氧阴离子孔（Ser(10)-Gly(50)-Asn(90))的存在。野生型酶能够水解对硝基苯乙酸酯、α-和β-萘乙酸酯，而 S10A 突变体完全失去了活性。使用圆二色性 (CD)、荧光、动态光散射 (DLS)、化学交联、电子显微镜 (EM) 和飞行时间 (TOF) 质谱研究了 Sm23 的结构特性。此外，用 1-丁基-3-甲基咪唑四氟硼酸盐观察到球形或球状聚集体，而用 1-丁基-3-甲基咪唑双(三氟甲基磺酰基)亚胺形成无定形聚集体。
