Structure‐based design of Nucleosome Binding Peptides for controlling cell function

Abstract

Proteins that bind the nucleosome, the repetitive unit of chromatin, and the histone H4 tail are critical to establishing chromatin architecture and phenotypic outcomes. A myriad of histone modifications, which strongly induce changes in chromatin structure, have been associated with malignancies and other diseases, highlighting the crucial role of chromatin architectural changes in disease mechanisms. The nucleosome surface was hypothesised as a therapeutic target, however the development, design and function of exogenous nucleosome binding molecules remain unclear.Herein, we performed structure‐based calculations on the nucleosome surface interaction to four peptides (NBMs), which present different nucleosome binding sites, derived from Nucleosome Binding Proteins (NBPs) to analyse the nucleosome sensitivity. Further, we were able to generate a new peptide (GMIP) with two nucleosome binding sites. A series of in vitro studies were performed to verify the impact of all these peptides on the nucleosome, showing differential action on its stability. We also demonstrated that GMIP and a canonical peptide may induce chromatin condensation in vitro. Confocal microscopy using labeled GMIP showed that it penetrates, by a passive mechanism, the cell and binds to chromatin. Cell‐based assays (MTT and FACS) showed that NBMs tested here presented a strong inhibitory activity on tumor cells, but not on non‐tumoral cells, proliferation and viability. It was also shown that these peptides might induce chromatin condensation in vivo. Besides that, the fish embryo toxicity (FET) test showed specificity in actions of NBMs on the ability to induce tissue modifications.Finally, we correlated the structural impact of NBMs to cellular function, providing a unique map on the nucleosome for designing new molecules with important implications. Taking all of this into account, it is clear that the is right to consider the nucleosome surface as a potential therapeutic target to regulate a plethora of cellular disorders.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.