Importance of structural tightening, as opposed to partially bound States, in the determination of chemical shift changes at noncovalently bonded interfaces |
| |
Authors: | Williams Dudley H Davies Nichola L Koivisto Jari J |
| |
Affiliation: | Department of Chemistry, Lensfield Road, Cambridge, CB2 1EW, UK. |
| |
Abstract: | Two models (A and B) have been proposed to account for decreased downfield chemical shifts of a proton bound by noncovalent interactions at a ligand/antibiotic interface as the number of ligand/antibiotic interactions is decreased. In model A, the proton involved in the noncovalent bond suffers a smaller downfield shift because the bond is, with a relatively large probability, broken, and not because it is longer. In model B, the proton involved in the noncovalent bond suffers a smaller downfield shift because the bond is longer, and not because it is, with a relatively large probability, broken. We show that model A cannot account for the chemical shift changes. Model B accounts for the process of positively cooperative binding, in which noncovalent bonds are reduced in length and thereby increase the stability of the organized state. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|