caa a22 4500 397558627 CHVBK 20180308164810.0 cr unu---uuuuu 161202e199611 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a021511 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a021511 Acid and Thermal Unfolding ofEseherichia coli Dihydrofolate Reductase [Elektronische Daten] [Eiji Ohmae, Toshiyuki Kurumiya, Shio Makino, Kunihiko Gekko] The acid and thermal unfolding of Escherichia coli dihydrofolate reductase (DHFR) were studied by means of circular dichroism (CD) and fluorescence spectroscopy. There existed at least one intermediate around pH 4 in the acid unfolding process at 15°C, in which the tertiary structure was disrupted before unfolding of the secondary structure. The fluorescence energy transfer from intrinsic tryptophan residues to 1-anilinonaphthalene-8-sul- fonate suggested the disruption of the tertiary structure around some tryptophan residues of the intermediate. The thermal unfolding process at pH 7.0 also involved at least one intermediate having a disrupted tertiary structure and a folded secondary structure. The three-state thermodynamic analysis showed that the intermediate in thermal unfolding was less stable by 1.8 kcal/mol than the native state. The similarity of the far-ultraviolet CD spectra of acid and thermally unfolded forms suggests that both types of unfolding produce the same structure, which may be a molten globule intermediate such as that in the folding kinetics of DHFR. The acid and thermal unfolding were depressed in the presence of KCl due to stabilization of the native form. © 1996 BY THE JOURNAL OF BIOCHEMISTRY Regular Papers nationallicence acid unfolding nationallicence dihydrofolate reductase nationallicence intermediate nationallicence molten globule nationallicence thermal unfolding nationallicence Ohmae Eiji Department of Materials Science and Graduate Department of Gene Science, Faculty of Science, Hiroshima University Kagamiyama, Higashi-Hiroshima, Hiroshima 739 aut Kurumiya Toshiyuki Department of Applied Biological Science, Faculty of Agriculture, Nagoya University Chikusa-ku, Nagoya, Aichi 464-01 aut Makino Shio Department of Applied Biological Science, Faculty of Agriculture, Nagoya University Chikusa-ku, Nagoya, Aichi 464-01 aut Gekko Kunihiko Department of Materials Science and Graduate Department of Gene Science, Faculty of Science, Hiroshima University Kagamiyama, Higashi-Hiroshima, Hiroshima 739 aut The Journal of Biochemistry Oxford University Press 120/5(1996-11), 946-953 0021-924X 120:5<946 1996 120 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a021511 text/html Onlinezugriff via DOI 1 other jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a021511 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ohmae Eiji Department of Materials Science and Graduate Department of Gene Science, Faculty of Science, Hiroshima University Kagamiyama, Higashi-Hiroshima, Hiroshima 739 aut NATIONALLICENCE 700 1- Kurumiya Toshiyuki Department of Applied Biological Science, Faculty of Agriculture, Nagoya University Chikusa-ku, Nagoya, Aichi 464-01 aut NATIONALLICENCE 700 1- Makino Shio Department of Applied Biological Science, Faculty of Agriculture, Nagoya University Chikusa-ku, Nagoya, Aichi 464-01 aut NATIONALLICENCE 700 1- Gekko Kunihiko Department of Materials Science and Graduate Department of Gene Science, Faculty of Science, Hiroshima University Kagamiyama, Higashi-Hiroshima, Hiroshima 739 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 120/5(1996-11), 946-953 0021-924X 120:5<946 1996 120 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford