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Structure of lysozyme dissolved in neat organic solvents as assessed by NMR and CD spectroscopies
Author(s) -
Knubovets Tatyana,
Osterhout John J.,
Klibanov Alexander M.
Publication year - 1999
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(19990420)63:2<242::aid-bit13>3.0.co;2-n
Subject(s) - formamide , ethylene glycol , chemistry , lysozyme , methanol , solvent , circular dichroism , dimethylformamide , proton nmr , protein tertiary structure , nuclear chemistry , organic chemistry , crystallography , biochemistry
The structure of the model protein hen egg‐white lysozyme dissolved in water and in five neat organic solvents (ethylene glycol, methanol, dimethylsulfoxide (DMSO), formamide, and dimethylformamide (DMF)) has been examined by means of 1 H NMR and circular dichroism (CD) spectroscopies. The NMR spectra of lysozyme reveal the lack of a defined tertiary structure in all five organic solvents, although the examination of line widths suggests the possibility of some ordered structure in ethylene glycol and in methanol. The near‐UV CD spectra of the protein suggest no tertiary structure in lysozyme dissolved in DMSO, formamide, and DMF, while a distinctive (albeit less pronounced than in water) tertiary structure is seen in ethylene glycol and a drastically changed one in methanol. A highly developed secondary structure was observed by far‐UV CD in ethylene glycol and methanol; interestingly, the α‐helix content of the protein in both was greater than in water, while the β‐structure content was lower. (Solvent absorbance in the far‐UV region prevents conclusions about the secondary structure in DMSO, formamide and DMF.) © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 63: 242–248, 19999.