Sequential Conformation Changes of Chinese Hamster Ovary Dihydrofolate Reductase at Its Active Sites

Title: Sequential Conformation Changes of Chinese Hamster Ovary Dihydrofolate Reductase at Its Active Sites

Volume: 12 Issue: 5

Author(s): Wen-he Zhang, San-bo Qin, Hong-jie Zhang and Zhi-yong Zhu

Affiliation:

Keywords: dhfr, tns, urea, fluorescence, activation mechanism, unfolding mechanism

Abstract: The local fluorescence probes, 2-(p-toluidino)-6-naphthalenesulfonic acid (TNS) and NADPH were employed to detect urea-induced conformation changes at each active site of dihydrofolate reductase (DHFR), respectively. The results indicate that local conformation change at DHF/TNS could be superimposed by the conformation change calculated from the enzyme activity change with a three-state model; while at NADPH site it is lagged in the first transition. This difference is further supported by the different relative changes of Michaelis constants at 0, 1 and 1.8 M urea for each substrate. Our results suggest that local conformation at DHF site is more flexible than that at NADPH site, and the urea-induced unfolding could be ascribed to a four-state transition.

Cite this article as:

Zhang Wen-he, Qin San-bo, Zhang Hong-jie and Zhu Zhi-yong, Sequential Conformation Changes of Chinese Hamster Ovary Dihydrofolate Reductase at Its Active Sites, Protein & Peptide Letters 2005; 12 (5) . https://dx.doi.org/10.2174/0929866054395310