S-to-alpha C radical migration in the radical cations of Gly-Cys and Cys-Gly

The radical cations of Cys-Gly and Gly-Cys were studied using ion-molecule reactions (IMR), infrared multiple-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations. Homolytic cleavage of the S-NO bond of nitrosylated precursors generated radical cations with the radical site initially located on the sulfur atom. Time-resolved ion-molecule reactions showed that radical site migration via hydrogen atom transfer (HAT) occurred much more quickly in Gly-Cys•+ than in Cys-Gly•+. IRMPD and DFT calculations indicated that for Gly-Cys, the radical migrated from the sulfur atom to the α-carbon of glycine, which is lower in energy than the sulfur radical (-53.5 kJ/mol). This migration does not occur for Cys-Gly because the glycine α-carbon is higher in energy than the sulfur radical (10.3 kJ/mol). DFT calculations showed that the highest energy barriers for rearrangement are 68.2 kJ/mol for Gly-Cys and 133.8 kJ/mol for Cys-Gly, which is in agreement with both the IMR and IRMPD data and explains the HAT in Gly-Cys

Structure and reactivity of the N-acetyl-cysteine radical cation and anion: does radical migration occur?

The structure and reactivity of the N-acetyl-cysteine radical cation and anion were studied using ion-molecule reactions, infrared multi-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations. The radical cation was generated by first nitrosylating the thiol of N-acetyl-cysteine followed by the homolytic cleavage of the S-NO bond in the gas phase. IRMPD spectroscopy coupled with DFT calculations revealed that for the radical cation the radical migrates from its initial position on the sulfur atom to the α-carbon position, which is 2.5 kJ mol-1 lower in energy. The radical migration was confirmed by time-resolved ion-molecule reactions. These results are in contrast with our previous study on cysteine methyl ester radical cation (Osburn et al., Chem. Eur. J. 2011 , 17, 873-879) and the study by Sinha et al. for cysteine radical cation (Phys. Chem. Chem. Phys. 2010 , 12, 9794-9800) where the radical was found to stay on the sulfur atom as formed. A similar approach allowed us to form a hydrogen-deficient radical anion of N-acetyl-cysteine, (M - 2H) •- . IRMPD studies and ion-molecule reactions performed on the radical anion showed that the radical remains on the sulfur, which is the initial and more stable (by 63.6 kJ mol-1) position, and does not rearrange

The Influences of Human Communication on Health Outcomes

This article examines the many assertions made in the health communication literature about the importance of communication as an essential process in promoting effective health care. If these assertions are true, then researchers should be able to demonstrate the ways in which communication influences the accomplishment of health care goals—how communication influences health outcomes. The links between health communication and health outcomes are examined, as well as the health outcomes literature. The authors propose a conceptual model of the role of communication in achieving advantageous outcomes in health care and health promotion based on the systems transformation model. The model can serve as a template for both guiding research on communication and health outcomes and for directing the health communication activities of interdependent participants in the modern health care system to promote desired health outcomes in health care/health promotion efforts.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline