caa a22 4500 475744152 CHVBK 20180406123508.0 cr unu---uuuuu 170329e20000401xx s 000 0 eng 10.1023/A:1007010818108 doi (NATIONALLICENCE)springer-10.1023/A:1007010818108 Alcohol-Induced Conformational Transitions in Ervatamin C. An α-Helix to β-Sheet Switchover [Elektronische Daten] [Monica Sundd, Suman Kundu, Medicherla Jagannadham] Alcohol-induced conformational transitions of erv C, a highly stable cysteine protease, were followed by CD, fluorescence, and activity. At acidic pH, the addition of different alcohols caused two types of conformational transitions. Increasing the concentration of nonfluorinated alkyl alcohols induced a conformational switch from α-helix to β-sheet. Under these conditions, the protein lost its proteolytic activity and tertiary structure. The switch was a sudden one, observed in 50% methanol, 45% ethanol, and 40% propanol. Under similar conditions of pH and concentration, however, glycerol and TFE enhanced the α-helicity of the protein. Methanol-induced denaturation was observed to occur in two stages; the first is the β-sheet state stabilized at low alcohol concentrations, and the other is the β-sheet state with enhanced ellipticity stabilized at high alcohol concentrations. This β-sheet conformation can be attained from the native as well as 6 M GuHCl-denatured state by addition of methanol and exhibits properties different from the native or unfolded state. This state shows loss of tertiary structure and activity, enhanced nonnative secondary structure, noncooperative temperature unfolding, and higher stability toward denaturants as compared to the native state, which are characteristic of the molten globule-like state or O-state, and thus this state may be functioning as an intermediate in the folding pathway of erv C. Plenum Publishing Corporation, 2000 Ervatamin C nationallicence physicochemical studies nationallicence conformational transitions nationallicence switchover nationallicence compact intermediate nationallicence β-sheet nationallicence Sundd Monica Molecular Biology Unit, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India aut Kundu Suman Molecular Biology Unit, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India aut Jagannadham Medicherla Molecular Biology Unit, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India aut Journal of Protein Chemistry Kluwer Academic Publishers-Plenum Publishers 19/3(2000-04-01), 169-176 0277-8033 19:3<169 2000 19 10930 https://doi.org/10.1023/A:1007010818108 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1007010818108 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sundd Monica Molecular Biology Unit, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India aut NATIONALLICENCE 700 1- Kundu Suman Molecular Biology Unit, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India aut NATIONALLICENCE 700 1- Jagannadham Medicherla Molecular Biology Unit, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India aut NATIONALLICENCE 773 0- Journal of Protein Chemistry Kluwer Academic Publishers-Plenum Publishers 19/3(2000-04-01), 169-176 0277-8033 19:3<169 2000 19 10930 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer