Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
Carbohydrate Enzyme Biotechnology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
Int J Biol Macromol. 2018 Jun;112:1104-1114. doi: 10.1016/j.ijbiomac.2018.02.037. Epub 2018 Feb 11.
The structure and biophysical properties of endo β-1,4-xylanase (PsGH10A) of family 10 glycoside hydrolase were characterized. The modeled PsGH10A structure showed classical (β/α)-barrel fold. Ramachandran plot displayed 99.1% residues in favored and 0.3% in the generously allowed region and only 0.6% residues in disallowed region. The secondary structure analysis of PsGH10A by CD revealed 31.75% α-helices 20.0% β-strands and 48.25% random coils. Protein melting study of PsGH10A showed complete unfolding at 60°C and did not require any metal ion for its stability. Structural superposition and docking analysis confirmed the involvement of Glu156 and Glu263 residues in catalysis. SAXS analysis displayed that PsGH10A is monomeric in nature showing fully folded state in solution form. Guinier analysis gave the radius of gyration (Rg) 2.23-2.29nm. Kratky plot indicated that the protein is fully folded globular shaped and flexible in solution form. The ab initio derived dummy model of PsGH10A displayed chicken thigh like shape. The ab initio derived dummy model superposed well with its comparative modeled structure except the N-terminal His-tag region.
对 10 家族内切 β-1,4-木聚糖酶（PsGH10A）的结构和生物物理特性进行了表征。建模的 PsGH10A 结构显示出经典的（β/α）-桶状折叠。Ramachandran 图谱显示 99.1%的残基处于有利区域，0.3%的残基处于宽松允许区域，只有 0.6%的残基处于不允许区域。通过 CD 对 PsGH10A 的二级结构分析显示，α-螺旋占 31.75%，β-折叠占 20.0%，无规卷曲占 48.25%。PsGH10A 的蛋白质融解研究表明，其在 60°C 时完全展开，且不需要任何金属离子来稳定。结构叠加和对接分析证实了Glu156 和 Glu263 残基在催化中的参与。SAXS 分析显示，PsGH10A 本质上是单体，在溶液中呈现完全折叠的状态。Guinier 分析给出了回转半径（Rg）为 2.23-2.29nm。Kratky 图谱表明，该蛋白质在溶液中完全折叠呈球形，具有柔韧性。PsGH10A 的从头计算得到的虚拟模型显示出鸡腿状的形状。从头计算得到的虚拟模型与比较建模结构除了 N 端 His 标签区域外，都很好地叠加。
