Optical fingerprinting of peptides using two-dimensional infrared spectroscopy: proof of principle.
We employ a particular form of two-dimensional infrared four-wave mixing (2DIR FWM) as a vibrational spectroscopic tool to quantify the amino acid content of a number of peptides. Vibrational features corresponding to ring modes of the aromatic groups of phenylalanine (Phe) and tyrosine (Tyr), as well as a methylene mode that is used as an internal reference, are identified. We show that the ratios of the integrated intensities, and the amplitudes, of the aromatic peaks of Phe and Tyr relative to the methylene integrated intensity, and amplitude, are proportional to the actual ratio of Phe and Tyr to CH(2) in the samples within a precision of +/-12.5%. This precision is shown to be sufficient to use this form of 2DIR spectroscopy as a possible proteins fingerprinting tool.
Molecular Dynamics Research Group, Department of Chemistry, Imperial College London, London SW7 2AZ, UK. f.fournier@imperial.ac.uk
Frédéric
F
Fournier
Elizabeth M
EM
Gardner
Rui
R
Guo
Paul M
PM
Donaldson
Laura M C
LM
Barter
D Jason
DJ
Palmer
Chris J
CJ
Barnett
Keith R
KR
Willison
Ian R
IR
Gould
David R
DR
Klug
D000596:Amino Acids / Q000032:analysis; D055095:Optics and Photonics; D010449:Peptide Mapping / Q000379:methods*; D012680:Sensitivity and Specificity; D013055:Spectrophotometry, Infrared / Q000379:methods*
D000596:Amino Acids