Alexander S. Moffett, Kyle W. Bender, Steven C. Huber, and Diwakar Shukla
Biophysical Journal, Volume 113, Issue 11, Pages 2354-2363, 2017.
Publication year: 2017

Abstract

Growing evidence supports the importance of protein S-glutathionylation as a regulatory post-translational modification with functional consequences for proteins. Discoveries of redox-state-dependent protein ki- nase S-glutathionylation have fueled discussion of redox-sensitive signaling. Following previously published experimental evidence for S-glutathionylation induced deactivation of the Arabidopsis thaliana BRASSINOSTEROID INSENSITIVE 1 (BRI1)-ASSOCIATED RECEPTOR-LIKE KINASE 1 (BAK1), we investigated the consequences of S-glutathionylation on the equilibrium conformational ensemble of BAK1 using all atom molecular dynamics simulations. We found that glutathionylation of C408 allosterically destabilizes the active-like state of BAK1 while stabilizing an inactive conformation known to recur in protein kinases. Glutathionylation of C408 also has structural consequences throughout the BAK1 kinase domain, while glu- tathionylation of C353 in the N-lobe and C374 near the ATP binding site have few notable effects on BAK1 as compared to the unmodified protein. Our results suggest an allosteric mechanism for inhibition of BAK1 by C408 S-glutathionylation, and more generally, support the notion of protein kinase S-glutationylation as a means of redox signaling in plant cells.