jp9b05118_si_002.avi (51.1 kB)
Vibrational Coupling on Stepwise Hydrogen Bond Formation of Amide I
media
posted on 2019-09-09, 14:49 authored by Anup GhoshDespite the key roles
of proteins and nucleic acids in biology,
understanding their labile structures and hydrogen bond interactions
with guest molecules has posed a critical challenge to the scientific
community. In this report, I have used dimethylformamide as a model
amide to account for amide hydrogen bond interactions of protein.
To quantify hydrogen bond conformation and the structural change,
I have monitored the amide I infrared (IR) stretching frequencies
while varying the pKa of phenol derivatives.
For all phenol derivatives, amide I has formed one hydrogen bond and
two hydrogen bond conformation. It has been observed that the formation
constant for one hydrogen bond is higher than that of two hydrogen
bonds for all phenol derivatives. During the formation of hydrogen
bond with amide I, IR absorbance of CC transition is enhanced
for all phenol derivatives. Enhancement of the IR absorbance of the
CC transition indicates hydrogen bond-assisted vibrational
coupling between the amide I and phenol ring transition. The relative
coupling constant is estimated to be higher for single hydrogen-bonded
conformer than the double hydrogen-bonded conformer. This is an intriguing
result as the frequency difference between the two coupled transitions
predicts otherwise. Using IR absorption spectroscopy, a delicate interplay
between hydrogen bonding conformations and intermolecular vibrational
coupling between amide I and H-bond donor phenol molecules has been
shown. This study can be used as a point of reference for understanding
the structural information of proteins, peptides, and nucleosides
having hydrogen bond interaction with any drug or ligand molecules.
My results as well provide an insight into the vibrational coupling
of carbonyl and CC transition of nucleobases.
History
Usage metrics
Categories
Keywords
Stepwise Hydrogen Bond Formationhydrogen bond interactionamide hydrogen bond interactionsH-bond donor phenol moleculeshydrogen-bonded conformerhydrogen bond conformationIR absorbancehydrogen bond interactionshydrogen bond-assisted vibrationalphenol derivativesIR absorption spectroscopyphenol ring transitionhydrogen bond
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC