TY - JOUR
T1 - Infrared probing of 4-Azidoproline conformations modulated by azido configurations
AU - Lee, Kyung Koo
AU - Park, Kwang Hee
AU - Joo, Cheonik
AU - Kwon, Hyeok Jun
AU - Jeon, Jonggu
AU - Jung, Hyeon Il
AU - Park, Sungnam
AU - Han, Hogyu
AU - Cho, Minhaeng
PY - 2012/5/3
Y1 - 2012/5/3
N2 - 4-Azidoproline (Azp) can tune the stability of the polyproline II (P II) conformation in collagen. The azido group in the 4R and 4S configurations stabilizes and destabilizes the PII conformation, respectively. To obtain insights into the dependence of the conformational stability on the azido configuration, we carried out Fourier transform (FT) IR experiments with four 4-azidoproline derivatives, Ac-(4R/S)-Azp-(NH/O)Me. We found that the amide I and azido IR spectra are different depending on the azido configuration and C-terminal structure. The origin of such spectral differences between 4R and 4S configurations and between C-terminal methylamide and ester ends was elucidated by quantum chemistry calculations in combination with 1H NMR and time- and frequency-resolved IR pump-probe spectroscopy. We found that the azido configurations and C-terminal structures affect intramolecular interactions, which are responsible for the ensuing conformational and thereby IR spectral differences. Consequently, 4-azidoproline conformations modulated by azido configurations can be probed by IR spectroscopy. These findings suggest that 4-azidoproline can be both a structure-control and -probing element, which enables the infrared tracking of proline roles in protein structure, function, and dynamics.
AB - 4-Azidoproline (Azp) can tune the stability of the polyproline II (P II) conformation in collagen. The azido group in the 4R and 4S configurations stabilizes and destabilizes the PII conformation, respectively. To obtain insights into the dependence of the conformational stability on the azido configuration, we carried out Fourier transform (FT) IR experiments with four 4-azidoproline derivatives, Ac-(4R/S)-Azp-(NH/O)Me. We found that the amide I and azido IR spectra are different depending on the azido configuration and C-terminal structure. The origin of such spectral differences between 4R and 4S configurations and between C-terminal methylamide and ester ends was elucidated by quantum chemistry calculations in combination with 1H NMR and time- and frequency-resolved IR pump-probe spectroscopy. We found that the azido configurations and C-terminal structures affect intramolecular interactions, which are responsible for the ensuing conformational and thereby IR spectral differences. Consequently, 4-azidoproline conformations modulated by azido configurations can be probed by IR spectroscopy. These findings suggest that 4-azidoproline can be both a structure-control and -probing element, which enables the infrared tracking of proline roles in protein structure, function, and dynamics.
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U2 - 10.1021/jp1085119
DO - 10.1021/jp1085119
M3 - Article
C2 - 22512849
AN - SCOPUS:84859528807
SN - 1520-6106
VL - 116
SP - 5097
EP - 5110
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 17
ER -