Adsorption kinetics, conformational change, and enzymatic activity of beta-glucosidase on hematite (alpha-Fe2O3) surfaces
Adsorption kinetics, conformational change, and enzymatic activity of beta-glucosidase on hematite (alpha-Fe2O3) surfaces
复制标题
β-葡萄糖苷酶在赤铁矿（α-Fe2O3）表面的吸附动力学、构象变化和酶活性
DOI：
10.1016/j.colsurfb.2020.111115
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Liu Juan
中科院分区：
文献类型：
--
作者：
Zang Yan;Liu Feng;Li Xiaoxu;Sheng Anxu;Zhai Junyi;Liu Juan
胞外酶的大部分与土壤矿物质密切相关，这可以保护酶免受土壤环境中的变性、沉淀、蛋白水解或微生物消耗。然而，矿物表面性质如何影响酶-矿物相互作用和矿物表面相关酶的酶活性仍然不清楚。采用原位衰减全反射傅里叶变换红外光谱（FTIR）和批实验研究了β-葡萄糖苷酶（BG）在赤铁矿（001）面和（104）面上的吸附行为、构象变化和酶活性。β-葡萄糖苷酶在赤铁矿（104）面上的吸附比在赤铁矿（001）面上的吸附发生更大的构象变化，这可能是由于（104）面上的蛋白质-表面相互作用较强，表面羟基密度相对较高。另一方面，在150分钟吸附实验结束时，吸附在赤铁矿（001）面上的BG的量几乎是吸附在赤铁矿（104）面上的BG的量的两倍，这是由于赤铁矿（104）面上的β-葡萄糖苷酶的构象变化程度更高。相应地，每克吸附在赤铁矿（104）面上的β-葡萄糖苷酶水解纤维二糖的初始速率是吸附在赤铁矿（001）面上的1.7倍。而在密度相同的条件下，纤维二糖在赤铁矿（001）面上的水解程度是在（104）面上的1.2倍，这是由于前者吸附的β-葡萄糖苷酶量较大。该研究解耦了矿物表面性质对土壤酶吸附动力学和构象变化的影响，为研究土壤环境中矿物表面性质与矿物相关酶催化活性之间的相关性提供了新的视角。
Substantial fractions of extracellular enzymes are intimately associated with soil minerals, which may protect enzymes from denaturation, precipitation, proteolysis, or microbial consumption in soil environments. However, how mineral surface properties affect enzyme-mineral interactions and enzymatic activity of enzymes associated to mineral surface is still unclear. In the present study, adsorption behavior, conformational change, and enzymatic activity of β-glucosidase (BG) on hematite (001) face and (104) face, respectively, were investigated using in situ attenuated total reflectance FTIR spectroscopy and batch experiments. β-glucosidase undergoes greater conformational changes upon adsorption onto hematite (104) face than on hematite (001) face, probably due to the stronger protein-surface interactions on (104) face with the relatively higher surface hydroxyl density. On the other hand, the amount of BG sorbed on hematite (001) face was nearly two times higher than that on hematite (104) at the end of the 150-min adsorption experiments, due to the higher extent of conformational change in β-glucosidase on hematite (104) face. Correspondingly, the initial rate of cellobiose hydrolysis by per gram of β-glucosidase adsorbed on hematite (104) face was 1.7 times higher than that on hematite (001) face. However, when the density of hematite particles was same, the extent of cellobiose hydrolysis was 1.2 times higher on hematite (001) face than that on the (104) face, because of the higher adsorbed amount of β-glucosidase on the former. This study decoupled the effects of mineral surface properties on adsorption kinetics and conformational changes of soil enzymes bound to soil minerals and provided new insights into the correlation between mineral surface properties and catalytical activity of mineral-associated enzymes in soil environments.