Vibrational spectra calculation of squamous cell carcinoma in the amide band region

Autor(es)

Bortoletto, Daiana R. ^[1] ; Lima, Cassio A. ^[2] ; Zezell, Denise ^[2] ; Sato, Erika T. ^[1] ; Martinho, H. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, Ctr Ciencias Nat & Humans, Av Estados 5001, BR-09210580 Santo Andre, SP - Brazil

^[2] IPEN CNEN SP, Inst Pesquisas Energet & Nucl, Ctr Lasers & Applicat, BR-05508000 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: VIBRATIONAL SPECTROSCOPY; v. 97, p. 135-139, JUL 2018.
• Citações Web of Science: 1

Resumo

Alterations in the amide (1500-1700 cm(-1)) spectral region probed by Fourier-transform infrared spectroscopy (FTIR) have been reported comparing tumor and normal tissues. Usually, bands in this range are assigned to the so-called Amide I, II, and III vibrations which provide pieces of information concerning peptide bonds and secondary structure (alpha-helix, beta-sheet) of proteins. Proteins folding changes due to tumoral process are usually considered to qualitatively explain the observed differences between tumor and normal tissues. In this paper, the observed changes in the FTIR spectra of squamous cell carcinoma compared to normal tissues were analyzed by First-Principles Density Functional Theory vibrational calculations. Computational models for skin and prototype beta-sheet model were employed. Our findings shown that predominates conjugated Amide I + Amide II, Amide V, methylene torsions, and ring side chains torsions and swings vibrations in this region. We also notice the lack of evidence concerning changes in the secondary structure of the beta-sheet peptidic model to explain the spectral differences. In fact, we concluded that the proline amino acid has the main rule to explain the data in this region being it responsible for the strong coupling between vibrations instead of water. (AU)

• Processo FAPESP: 11/19924-2 - Estudo e desenvolvimento de novos materiais avançados: eletrônicos, magnéticos e nanoestruturados: uma abordagem interdisciplinar
• Beneficiário: Carlos Rettori
• Modalidade de apoio: Auxílio à Pesquisa - Temático