Two-photon circular dichroism of molecular structures simulating l-tryptophan residues in proteins with secondary structures

• Published in: Chemical physics letters 2014-05, Vol.601, p.6-12
• Main Authors: Vesga, Yuly, Diaz, Carlos, Higgs, Mary, Hernandez, Florencio E.
• Format: Article
• Language: English
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2014.03.083

[Display omitted] •Analysis of the theoretical TPCD spectra of Trp residues in proteins with secondary structures.•TPCD spectra of the Trp residues in each configuration reveal fingerprints down to the FUV.•Results show that the main-chain angles are affected by the side-chain configuration and vice-versa.•FUV-TPCD can help identifying conformation of amino acid residues in relatively complex structures. Herein, we report on the calculation and the comparative analysis of the theoretical two-photon circular dichroism (TPCD) spectra of l-tryptophan (Trp) residues in proteins with secondary structures (α-helix, β-strand and random coil) conformation, down to the far-UV region (FUV). The examination of the TPCD spectra of the different conformers in each configuration reveals distinctive fingerprints in the FUV, a dark spectral region for electronic circular dichroism (ECD). Our results show the potential of FUV-TPCD to identify and study protein structures in a region never assessed before but filled with important structural information.