Design of peptidase ‐resistant peptide inhibitors of myosin light chain kinase

Myosin light chain kinase (MLCK) is a key regulator of various forms of cell motility including smooth muscle contraction, cell migration, cytokinesis, receptor capping, secretion, etc. Inhibition of MLCK activity in endothelial and epithelial monolayers using cell‐permeant peptide Arg‐Lys‐Lys‐Tyr‐Lys‐Tyr‐Arg‐Arg‐Lys (PIK, Peptide Inhibitor of Kinase) allows protecting the barrier capacity, suggesting a potential medical use of PIK. However, low stability of L‐PIK in a biological milieu prompts for development of more stable L‐PIK analogues for use as experimental tools in basic and drug‐oriented biomedical research. Previously, we designed PIK1, H‐(NαMe)Arg‐Lys‐Lys‐Tyr‐Lys‐Tyr‐Arg‐Arg‐Lys‐NH2, that was 2.5‐fold more resistant to peptidases in human plasma in vitro than L‐PIK and equal to it as MLCK inhibitor. In order to further enhance proteolytic stability of PIK inhibitor, we designed the set of six site‐protected peptides based on L‐PIK and PIK1 degradation patterns in human plasma as revealed by 1H‐NMR analysis. Implemented modifications increased half‐live of the PIK‐related peptides in plasma about 10‐fold, and these compounds retained 25–100% of L‐PIK inhibitory activity toward MLCK in vitro. Based on stability and functional activity ranking, PIK2, H‐(NαMe)Arg‐Lys‐Lys‐Tyr‐Lys‐Tyr‐Arg‐D‐Arg‐Lys‐NH2, was identified as the most stable and effective L‐PIK analogue. PIK2 was able to...

Source: Journal of Peptide Science - August 31, 2016 Category: Biochemistry Authors: Asker Y. Khapchaev, Olga A. Kazakova, Mikhail V. Samsonov, Maria V. Sidorova, Valery N. Bushuev, Elena L. Vilitkevich, Andrey A. Az'muko, Alexander S. Molokoedov, Zhanna D. Bespalova, Vladimir P. Shirinsky Tags: Research Article Source Type: research