Involvement of the N Domain Residues E34, K35, and R38 in the Functionally Active Structure of Escherichia coli Lon Protease

• Published in: Actanaturae 2020-10, Vol.12 (4), p.86-97
• Main Authors: Andrianova, A G, Kudzhaev, A M, Abrikosova, V A, Gustchina, A E, Smirnov, I V, Rotanova, T V
• Format: Article
• Language: English
• ISSN: 2075-8251
• DOI: 10.32607/actanaturae.11197

ATP-dependent Lon protease of ( Lon), which belongs to the superfamily of AAA proteins, is a key component of the cellular proteome quality control system. It is responsible for the cleavage of mutant, damaged, and short-lived regulatory proteins that are potentially dangerous for the cell. Lon functions as a homooligomer whose subunits contain a central characteristic AAA module, a C-terminal protease domain, and an N-terminal non-catalytic region composed of the actual N-terminal domain and the inserted α-helical domain. An analysis of the N domain crystal structure suggested a potential involvement of residues E34, K35, and R38 in the formation of stable and active Lon. We prepared and studied a triple mutant LonEKR in which these residues were replaced with alanine. The introduced substitutions were shown to affect the conformational stability and nucleotide-induced intercenter allosteric interactions, as well as the formation of the proper protein binding site.