Novel Use for the Osmolyte Trimethylamine N-oxide: Retaining the Psychrophilic Characters of Cold-Adapted Protease Deseasin MCP-01 and Simultaneously Improving its Thermostability

作者：He Hai Lun; Chen Xiu Lan; Zhang Xi Ying; Sun Cai Yun; Zou Bai Chen; Zhang Yu Zhong^*

来源：Marine Biotechnology, 2009, 11(6): 710-716.

DOI：10.1007/s10126-009-9185-2

• Cold-adapted enzyme
• Deseasin MCP-01
• Trimethylamine N-oxide (TMAO)
• Cold-adaption
• Thermostability

The low thermostability of cold-adapted enzymes is a main barrier for their application. A simple and reliable method to improve both the stability and the activity of cold-adapted enzymes is still rare. As a protein stabilizer, the effect of trimethylamine N-oxide (TMAO) on a cold-adapted enzyme or protein has not been reported. In this study, effects of TMAO on the structure, activity, and stability of a cold-adapted protease, deseasin MCP-01, were studied. Deseasin MCP-01 is a new type of subtilase from deep-sea psychrotolerant bacterium Pseudoalteromonas sp. SM9913. Fluorescence and CD spectra showed that TMAO did not perturb the structure of MCP-01 and therefore kept the conformational flexibility of MCP-01. One molar TMAO improved the activity of MCP-01 by 174% and its catalytic efficiency (k (cat) /K (m)) by 290% at 0A degrees C. In the presence of 1 M TMAO, the thermostability (t (1/2)) of MCP-01 increased by two- to fivefold at 60 similar to 40A degrees C. Structural analysis with CD showed that 1 M TMAO could keep the structural thermostability of MCP-01 close to that of its mesophilic counterpart subtilisin Carlsberg when incubated at 40A degrees C for 1 h. Moreover, 1 M TMAO increased the melting temperature (T (m)) of MCP-01 by 10.5A degrees C. These results suggest that TMAO can be used as a perfect stabilizing agent to retain the psychrophilic characters of a cold-adapted enzyme and simultaneously improve its thermostability.

• 出版日期2009-12
• 单位山东大学