Utilizing dipole-dipole cross-correlated relaxation for the measurement of angles between pairs of opposing C αHα-CαHα bonds in anti-parallel β-sheets

Publication date: Available online 12 April 2018 Source:Methods Author(s): T. Michael Sabo, Vytautas Gapsys, Korvin F.A. Walter, R. Bryn Fenwick, Stefan Becker, Xavier Salvatella, Bert L. de Groot, Donghan Lee, Christian Griesinger Dipole-dipole cross-correlated relaxation (CCR) between two spin pairs is rich with macromolecular structural and dynamic information on inter-nuclear bond vectors. Measurement of short range dipolar CCR rates has been demonstrated for a variety of inter-nuclear vector spin pairs in proteins and nucleic acids, where the multiple quantum coherence necessary for observing the CCR rate is created by through-bond scalar coupling. In principle, CCR rates can be measured for any pair of inter-nuclear vectors where coherence can be generated between one spin of each spin pair, regardless of both the distance between the two spin pairs and the distance of the two spins forming the multiple quantum coherence. In practice, however, long range CCR (lrCCR) rates are challenging to measure due to difficulties in linking spatially distant spin pairs. By utilizing through-space relaxation allowed coherence transfer (RACT), we have developed a new method for the measurement of lrCCR rates involving CαHα bonds on opposing anti-parallel β-strands. The resulting lrCCR rates are straightforward to interpret since only the angle between the two vectors modulates the strength of the interference effect. We applied our lrCCR measurement to the third immunog...
Source: Methods - Category: Molecular Biology Source Type: research