title: Monitoring potential molecular interactions of adenine with other amino acids using Raman spectroscopy and DFT modeling.
abstract: We report on the modes of inter-molecular interaction between adenine (Ade) and the amino acids: glycine (Gly), lysine (Lys) and arginine (Arg) using Raman spectroscopy of binary mixtures of adenine and each of the three amino acids at varying molar ratios in the spectral region 1550-550 cm(-1). We focused our attention on certain specific changes in the Raman bands of adenine arising due to its interaction with the amino acids. While the changes are less apparent in the Ade/Gly system, in the Ade/Lys or Ade/Arg systems, significant changes are observed, particularly in the Ade Raman bands that involve the amino group moiety and the N7 and N1 atoms of the purine ring. The ν(N1-C6), ν(N1-C2), δ(C8-H) and δ(N7-C8-N9) vibrations at 1486, 1332, 1253 and 948 cm(-1) show spectral changes on varying the Ade to amino acid molar ratio, the extent of variation being different for the three amino acids. This observation suggests a specific interaction mode between Ade and Lys or Arg, which is due to the hydrogen bonding. The measured spectral changes provide a clear indication that the interaction of Ade depends strongly on the structures of the amino acids, especially their side chains. Density functional theory (DFT) calculations were carried out to elucidate the most probable interaction modes of Ade with the different amino acids.
authors.affiliation: Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005, India. Electronic address: shwetasinghbhu@gmail.com.
authors.forename: Shweta
authors.initials: S
authors.lastname: Singh
authors.affiliation: School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Donfack
authors.affiliation: Department of Pure and Applied Physics, Guru Ghasidas University, Main Campus, Koni, Bilaspur 495009, India.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Srivastava
authors.affiliation: Department of Physics, Sogang University, Seoul 121-742, South Korea.
authors.forename: Dheeraj K
authors.initials: DK
authors.lastname: Singh
authors.affiliation: School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Materny
authors.affiliation: Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005, India.
authors.forename: B P
authors.initials: BP
authors.lastname: Asthana
authors.affiliation: Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005, India.
authors.forename: P C
authors.initials: PC
authors.lastname: Mishra
mesh_terms: D000225:Adenine / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D012996:Solutions; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics; D014732:Vibration
chemical_list: D000596:Amino Acids; D012996:Solutions; D000225:Adenine
keywords: Adenine; Amino acids; DFT calculations; Molecular interactions; Raman spectroscopy