Brittney A. Klein, Béla Reiz, Ian M. Robertson, Malcolm Irving, Liang Li , Yin-Biao Sun, and Brian D. Sykes
Biochemistry, 2018
doi: 10.1021/acs.biochem.8b00109
The development of calcium sensitizers for the treatment of systolic heart failure presents difficulties, including judging the optimal efficacy and the specificity to target cardiac muscle. The thin filament is an attractive target because cardiac troponin C (cTnC) is the site of calcium binding and the trigger for subsequent contraction. One widely studied calcium sensitizer is levosimendan. We have recently shown that when a covalent cTnC–levosimendan analogue is exchanged into cardiac muscle cells, they become constitutively active, demonstrating the potency of a covalent complex. We have also demonstrated that levosimendan reacts in vitro to form a reversible covalent thioimidate bond specifically with cysteine 84, unique to cTnC. In this study, we use mass spectrometry to show that the in vitro mechanism of action of levosimendan is consistent with an allosteric, reversible covalent inhibitor; to determine whether the presence of the cTnI switch peptide or changes in either Ca2+ concentration or pH modify the reaction kinetics; and to determine whether the reaction can occur with cTnC in situ in cardiac myofibrils. Using the derived kinetic rate constants, we predict the degree of covalently modified cTnC in vivo under the conditions studied. We observe that covalent bond formation would be highest under the acidotic conditions resulting from ischemia and discuss whether the predicted level could be sufficient to have therapeutic value. Irrespective of the in vivo mechanism of action for levosimendan, our results provide a rationale and basis for the development of reversible covalent drugs to target the failing heart.
A blog highlighting recent publications in the area of covalent modification of proteins, particularly relating to covalent-modifier drugs. @CovalentMod on Twitter and @covalentmod@mstdn.science on Mastodon
Covalent drug discovery using sulfur(VI) fluoride exchange warheads
Huang Huang, Lyn H. Jones Expert Opinion on Drug Discovery , 2023 https://doi.org/10.1080/17460441.2023.2218642 Covalent drug discovery has ...
-
Zhao, Z.; Bourne, P. E. ChemRxiv 2022 . https://doi.org/10.26434/chemrxiv-2022-nlb0m Kinase-targeted drug discovery for cancer therapy ha...
-
Wang, S.; Hadisurya, M.; Tao, W. A.; Dykhuizen, E.; Krusemark, C. ChemRxiv 2022 . https://doi.org/10.26434/chemrxiv-2022-tvgn1 Targeted co...
-
Jian Ding, Guo Li, Hejun Liu, Lulu Liu, Ying Lin, Jingyan Gao, Guoqiang Zhou, Lingling Shen, Mengxi Zhao, Yanyan Yu, Weihui Guo, Ulrich Homm...