Jump to main content
Jump to site search
SCHEDULED MAINTENANCE Close the message box

Maintenance work is planned for Monday 16 August 2021 from 07:00 to 23:59 (BST).

Website performance may be temporarily affected and you may not be able to access some PDFs or images. If this does happen, refreshing your web browser should resolve the issue. We apologise for any inconvenience this might cause and thank you for your patience.


Issue 8, 2016

Quantitative evaluation of positive ϕ angle propensity in flexible regions of proteins from three-bond J couplings

Author affiliations

Abstract

3 J HNHα and 3JC′C′ couplings can be readily measured in isotopically enriched proteins and were shown to contain precise information on the backbone torsion angles, ϕ, sampled in disordered regions of proteins. However, quantitative interpretation of these couplings required the population of conformers with positive ϕ angles to be very small. Here, we demonstrate that this restriction can be removed by measurement of 3JC′Hα values. Even though the functional forms of the 3JC′Hα and 3JHNHα Karplus equations are the same, large differences in their coefficients enable accurate determination of the fraction of time that positive ϕ angles are sampled. A four-dimensional triple resonance HACANH[C′] E.COSY experiment is introduced to simultaneously measure 3JC′Hα and 3JHNC′ in the typically very congested spectra of disordered proteins. High resolution in these spectra is obtained by non-uniform sampling (in the 0.1–0.5% range). Application to the intrinsically disordered protein α-synuclein shows that while most residues have close-to-zero positive ϕ angle populations, up to 16% positive ϕ population is observed for Asn residues. Positive ϕ angle populations determined with the new approach agree closely with consensus values from protein coil libraries and prior analysis of a large set of other NMR parameters. The combination of 3JHNC′ and 3JC′C′ provides information about the amplitude of ϕ angle dynamics.

Graphical abstract: Quantitative evaluation of positive ϕ angle propensity in flexible regions of proteins from three-bond J couplings

Supplementary files

Article information


Submitted
31 Jul 2015
Accepted
21 Sep 2015
First published
21 Sep 2015

Phys. Chem. Chem. Phys., 2016,18, 5759-5770
Article type
Paper
Author version available

Quantitative evaluation of positive ϕ angle propensity in flexible regions of proteins from three-bond J couplings

J. H. Lee, J. Ying and A. Bax, Phys. Chem. Chem. Phys., 2016, 18, 5759 DOI: 10.1039/C5CP04542H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.


Social activity

Search articles by author

Spotlight

Advertisements