Assessing the structural integrity of a lyophilized protein in organic solvents

Journal Article · Wed Apr 12 04:00:00 EDT 1995 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja00119a007· OSTI ID:41837

Desai, U R; Klibanov, A M ^[1]

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1. Massachusetts Inst. of Technology, Cambridge, MA (United States)

The structure of a model protein, bovine pancreatic trypsin inhibitor (BPTI), in organic solvents has been examined using hydrogen isotope exchange/high-resolution NMR methodology. When lyophilized deuterated BPTI is suspended in acetonitrile, tetrahydrofuran, ethyl acetate, or butanol, each containing 1% {sup 1}H{sub 2}O, several protein amide protons that are buried and strongly hydrogen bonded in aqueous solution are found to exchange with the solvent significantly within 24 h. When solid BPTI is prepared by different methods, such as rotary evaporation, acetone precipitation, or lyophilization from a dimethyl sulfoxide solution, and subsequently suspended in acetonitrile containing 1% water, the exchange intensities of the amide protons vary greatly among the preparations. These data combined suggest that the structure of BPTI in the four aforementioned organic solvents is partially unfolded, but not more so than in lyophilized powder, i.e., that these solvents cause little additional protein denaturation beyond that brought about by lyophilization. Using the same methodology, the BPTI structure also has been studied in several protein-dissolving solvents containing 1% water. In dimethyl sulfoxide, dimethylformamide, or methanol, the same amide protons exchange almost completely within 24 h, while in glycerol they do not. 33 refs., 3 figs., 2 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 41837
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 14 Vol. 117; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
55 BIOLOGY AND MEDICINE
BASIC STUDIES
DISSOLUTION
EXPERIMENTAL DATA
LYOPHILIZATION
MOLECULAR STRUCTURE
NMR SPECTRA
NUMERICAL DATA
PROTEINS
SOLVENTS