Deciphering the role of lysine mutation in the stability and dynamics of the Cren7-DNA complex.

Abstract

Cren7, a conserved chromatin protein in Crenarchaeota, organizes and stabilizes genomic DNA. The chromatin protein Cren7 plays a key role in maintaining DNA architecture and stability in hyperthermophilic archaea. Its interaction with DNA is largely mediated by positively charged lysine residues that establish strong electrostatic and hydrogen-bond interactions with the negatively charged phosphate backbone. In this study, we investigated how lysine mutations affect the structural stability and dynamics of the Cren7-DNA complex using all-atom molecular dynamics simulations. Comparative analyses between the wild-type and lysine-to-alanine mutants revealed noticeable perturbations in the DNA stability as well as complex stability via the protein-DNA interface. These results reflect the importance of lysine residues, with Lys48, Lys53, and Lys24 having the highest impact on the Cren7-DNA stability. Furthermore, this study demonstrates that the differential effects of lysine mutations on DNA stability in the Cren7-DNA complex not only depend on the position of the mutated residue in the same Cren7 but also reflect the combined effects of the protein position, DNA sequence, and coupling.

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