title: Combined use of spectroscopic and energy calculation methods for the determination of peptide conformation in solution.
abstract: This paper describes the combined use of energy calculations and spectroscopic data for the determination of peptide conformations in solution. The approach involves (i) experimental measurements of spectroscopic parameters for a molecule, (ii) calculation of these parameters for low-energy conformers previously determined with regard to local fluctuations in conformation and (iii) a random search for statistically weighted combinations of conformers which provide a good agreement between the calculated and experimental data. The above approach was used to study the conformation of a spin-labelled angiotensin molecule (SL-AT). It appears that the C-terminal hexapeptide of SL-AT possesses two geometrically different spatial forms of the backbone in aqueous solution, with mean values for the statistical weight of 0.78 and 0.22, respectively. In contrast, the N-terminal part of the molecule is conformationally labile. The data obtained can be used to describe the conformation of angiotensin in solution.
authors.affiliation: Institute of Organic Synthesis, Latvian S.S.R. Academy of Sciences, Aizkraukles, U.S.S.R.
authors.forename: G V
authors.initials: GV
authors.lastname: Nikiforovich
authors.forename: B G
authors.initials: BG
authors.lastname: Vesterman
authors.forename: J
authors.initials: J
authors.lastname: Betins
mesh_terms: D000804:Angiotensin II; D008958:Models, Molecular; D010455:Peptides; D011487:Protein Conformation; D012996:Solutions; D013053:Spectrophotometry; D013113:Spin Labels; D013816:Thermodynamics
chemical_list: D010455:Peptides; D012996:Solutions; D013113:Spin Labels; D000804:Angiotensin II