Issue 35, 2018

Nuclear spin singlet states as magnetic on/off probes in self-assembling systems

Abstract

Self-assembling processes occur in a variety of compounds such as peptides, proteins and DNA. These processes have been linked to pathologies and have as well been exploited for designing responsive contrast agents for disease detection. Novel methods to investigate and detect self-assembly therefore hold promise to obtain more insights into disease progression or open pathways to the design of novel self-assembling materials. In this article we are introducing nuclear singlet states to probe self-assembly in the dipeptide isoleucine–phenylalanine (IF) as a thermoresponsive on/off switch for nuclear magnetic resonance (NMR). We have investigated the relaxation and singlet state properties of the β-protons of phenylalanine in the IF dipeptide in aqueous solutions. At IF concentrations of 2 wt% and above 308 K, a long lived nuclear singlet state, as compared to the longitudinal relaxation, was observed. At 308 K the dipeptide starts forming a gel and no singlet state is accessible at lower temperatures. Upon heating, the gel disassembles and an isotropic liquid forms making the singlet state accessible again. This demonstrates the thermoresponsive on–off character of the nuclear spin singlet state in the IF dipeptide.

Graphical abstract: Nuclear spin singlet states as magnetic on/off probes in self-assembling systems

Article information

Article type
Paper
Submitted
13 Jul 2018
Accepted
14 Aug 2018
First published
14 Aug 2018
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2018,20, 22463-22467

Nuclear spin singlet states as magnetic on/off probes in self-assembling systems

S. Mamone and S. Glöggler, Phys. Chem. Chem. Phys., 2018, 20, 22463 DOI: 10.1039/C8CP04448A

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