An electronic effect on protein structure |
| |
Authors: | Hinderaker Matthew P Raines Ronald T |
| |
Institution: | Department of Chemistry and Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA. |
| |
Abstract: | The well-known preference of the peptide bond for the trans conformation has been attributed to steric effects. Here, we show that a proline residue with an N-formyl group (H(i-1)-C'(i-1)=O(i-1)), in which H(i-1) presents less steric hindrance than does O(i-1), likewise prefers a trans conformation. Thus, the preference of the peptide bond for the trans conformation cannot be explained by steric effects alone. Rather, an n --> pi* interaction between the oxygen of the peptide bond (O(i-1)), and the subsequent carbonyl carbon in the polypeptide chain (C'(i)) also contributes to this preference. The O(i-1) and C'(i) distance and O(i-1).C'(i)=O(i) angle are especially favorable for such an n --> pi* interaction in a polyproline II helix. We propose that this electronic effect provides substantial stabilization to this and other elements of protein structure. |
| |
Keywords: | Bürgi‐Dunitz trajectory collagen hyperconjugation peptide bond polyproline II helix proline isomerization stereoelectronic effect steric effect |
本文献已被 PubMed 等数据库收录! |
|