Functional characterization of a thermostable methionine adenosyltransferase from Thermus thermophilus HB27
Yanhui Liu, Biqiang Chen, Zheng Wang, Luo Liu, Tianwei Tan
Frontiers of Chemical Science and Engineering
MATTt (a thermostable methionine adenosyltransferase from Thermus thermophilusHB27) was overexpressed in Escherchia coli and purified using Ni-NTA affinity column. The enzymatic activity of MATTt was investigated in a temperature range from 30 °C to 90 °C, showing that MATTt exhibited a high enzymatic activity and good thermostability at 80 °C. Circular dichroism spectra reveals that MATTt contains high portion of β-sheet structures contributing to the thermostability of MATTt. The kinetic parameter, K m is 4.19 mmol/L and 1.2 mmol/L for ATP and methionine, respectively. MATTt exhibits the highest enzymatic activity at pH 8. Cobalt (Co2+) and zinc ion (Zn2+) enhances remarkably the activity of MATTt compared to the magnesium ion (Mg2+). All these results indicated that the thermostable MATTt has great potential for industry applications.
Circular dichroism, Thermal stability, Secondary structure, Biochemistry