Now showing items 11-20 of 119
Vibrational analysis of peptides, polypeptides, and proteins. XVIII. Conformational sensitivity of the Α-helix spectrum: Α I - and Α II -Poly( L -alanine)
(Wiley Subscription Services, Inc., A Wiley Company, 1984-05)
The Α II -helix (φ = −70.47°, Ψ = −35.75°) is a structure having the same n and h as the (standard) Α I -helix (φ = −57.37°, Ψ = −47.49°). Its conformational angles are commonly found in proteins. Using an improved ...
Ab initio force fields of alanine dipeptide in four non-hydrogen bonded conformations
(Elsevier, 1990-03)
We have previously calculated the force fields and dipole-moment derivatives of the L-alanyl dipeptide, CH3CONHCHCH2CONHCH3, in the C5, C7eq, and C7ax conformations with intramolecular NH...OC hydrogen bonding. We have now ...
A quantitative anharmonic analysis of the amide A band in α-helical poly( L -alanine)
(John Wiley & Sons, Inc., 1999-03)
Polarized ir spectra of oriented films of α-helical poly( l -alanine) (α-PLA) have been obtained as a function of residual solvent dichloroacetic acid (DCA). The amide A, B, II, and V regions exhibit multiple bands whose ...
Construction of molecular mechanics energy functions by mathematical transformation of ab initio force fields and structures
(John Wiley & Sons, Inc., 1991-04)
A method is presented by which ab initio (or empirical) force fields and structures can be converted to molecular mechanics energy parameters. Using Cartesian coordinates, the effect of van der Waals and other nonquadratic ...
Vibrational analysis of conformation in peptides, polypeptides, and proteins This is paper number 16 in a series of which Ref. 20 is paper 15.
(Wiley Subscription Services, Inc., A Wiley Company, 1983-01)
A vibrational force field for the polypeptide chain has been developed for normal-mode analysis of such molecules. It can reproduce observed frequencies of known structures to within about 5 cm −1 . We review the application ...
Vibrational analysis of 2,2,3-trichlorobutane and a force field for 2,2-dichloropropane
(Elsevier, 1990)
The infrared and Raman spectra of 2,2,3-dichlorobutane have been analysed in terms of normal modes calculated from a force field for secondary dichlorides refined using this molecule as well as 2,2-dichlorobutane and ...
Observation of coupled quasi-two-dimensional electronic excitations in tilted magnetic fields
(Elsevier, 1988)
We report on a magneto-Raman scattering investigation of free and donor-bound electrons in GaAs/AlxGa1-xAs quantum wells. For fields perpendicular to the layers, the spectra show intersubband transitions of photoexcited ...
Conformation dependence of the SH and CS stretch frequencies of the cysteine residue
(Wiley Subscription Services, Inc., A Wiley Company, 1992-11)
In order to relate the observed SH and CS stretch frequencies of the cysteine residue in proteins more closely to its conformation, we have done normal mode calculations on a model for this structure, viz., (CCONH)(CNHCO)CHCH ...
Conformers of cis-N-methylacetamide : Ab initio study of geometries and vibrational spectra
(Elsevier, 1991-11-01)
Energies and geometries have been obtained, at the Hartree-Fock 4-31G* level, for the four stable conformers of cis-N-methylacetamide that result from conformational isomerism of the CH3 groups. Ab initio force fields were ...
Vibrational analysis of peptides, polypeptides, and proteins. I. Polyglycine I
(Wiley Subscription Services, Inc., A Wiley Company, 1976-12)
A force field has been refined for the antiparallel chain-rippled sheet structure of polyglycine I. Transition dipole coupling and hydrogen bonding are explicitly taken into account. Amide I and amide II mode splittings ...