Abstract |
Beta- azidoalanine dipeptide 1 was synthesized, and its azido stretching vibration in H2O and dimethyl sulfoxide ( DMSO) was studied by using Fourier transform (FT) IR spectroscopy. The dipole strength of the azido stretch mode is found to be about 19 and 5 times larger than those of the CN and SCN stretch modes, respectively, which have been used as local environmental IR sensors. The azido stretch band in H2O is blue-shifted by about 14 cm(-1) in comparison to that in DMSO, indicative of its sensitivity to the electrostatic environment. To test the utility of beta- azidoalanine as an IR probe of the local electrostatic environment in proteins, azidopeptide 4 was prepared by its incorporation into Abeta(16-22) peptide of the Alzheimer's disease amyloid beta-protein at position Ala21. The amide I IR spectrum of 4 in D2O suggests that the azidopeptide thus modified forms in-register beta-sheets in aggregates as observed for normal Abeta(16-22). The azido peak frequency of 4 in aggregates is almost identical to that in DMSO, indicating that the azido group is not exposed to water but to the hydrophobic environment. We believe that beta- azidoalanine will be used as an effective IR probe for providing site-specific information about the local electrostatic environments of proteins.
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Authors | Kwang-Im Oh, Joo-Hyun Lee, Cheonik Joo, Hogyu Han, Minhaeng Cho |
Journal | The journal of physical chemistry. B
(J Phys Chem B)
Vol. 112
Issue 33
Pg. 10352-7
(Aug 21 2008)
ISSN: 1520-6106 [Print] United States |
PMID | 18671422
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Amides
- Amino Acids
- Amyloid
- Azides
- Peptides
- Solvents
- Water
- azidoalanine
- Alanine
- Dimethyl Sulfoxide
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Topics |
- Alanine
(analogs & derivatives, chemistry)
- Amides
- Amino Acids
(chemistry)
- Amyloid
(chemistry)
- Azides
(chemistry)
- Chemistry, Physical
(methods)
- Dimethyl Sulfoxide
(chemistry)
- Models, Chemical
- Peptides
(chemistry)
- Protein Folding
- Protein Structure, Secondary
- Sensitivity and Specificity
- Solvents
(chemistry)
- Spectrophotometry, Infrared
(instrumentation, methods)
- Static Electricity
- Water
(chemistry)
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