Dynamical Structure of Peptide Molecules

Abstract

In view of the importance of the peptide linkage in structural biology, we have carried out intensive investigations on peptide molecules consisting of a peptide linkage with one or two substituents in the gas phase by Fourier transform microwave spectroscopy, paying special attention to the internal rotation of the substituents relative to the central linkage framework. We have found that, in sharp contrast with the stiff structure around the central C-N bond of the linkage, the internal rotations of the substituents are of low frequency and thus of large amplitude and are extremely susceptible to their local environment such as the presence of other substituents.

Fourier transform microwave spectroscopy of N,N-dimethylacetamide

“…The present results are somewhat surprising when compared with the results for trans-N-methylacetamide, for which barrier heights were determined to be V 3 = 79.06(9) cm À1 for the N-methyl top and V 3 = 73.047(5) cm À1 for the trans-C-methyl top [1]. Although an atom or a group located at Y seems to play an important qualitative role in determining the barrier to internal rotation of methyl tops located at X and Y 0 as discussed in the article on the dynamical structure of peptide molecules written by Hirota and co-workers [9], further consideration will be necessary to understand correctly how to transfer the behavior of internal rotations in this molecule to internal rotations in related peptide molecules.…”

Absolute cross sections for elastic electron scattering from methylformamide

“…Therefore, NMF has been considered as a model compound to investigate electron collisions from protein constituents. Kawashima and coauthors [13] have recently carried out a detailed investigation on the dynamical structure of peptide molecules. NMF has a planar structure, with two different isomers depending on the position of the CH 3 group (trans-NMF is presented in Fig.…”

Dynamical structure of peptide molecules: Fourier transform microwave spectroscopy and ab initio calculations of N-methylformamide

“…Our group has been applying Fourier transform microwave (abbreviated as FTMW) spectroscopy to a few peptide molecules, as reviewed in Ref. [1], where our earlier results are summarized.…”