Mutations to a glycine loop in the catalytic site of human Lon changes its protease, peptidase and ATPase activities

• DOI: 10.1111/febs.12740
• Publication Date: 2014-02-12T16:53:41Z
• Authors: Ľuboš Ambro; Vladimír Pevala; Gabriela Ondrovičová; Jana Bellová; Nina Kunová; Eva Kutejová; Jacob Bauer
• Keywords: Cleave; Proteolysis

Lon, also called protease La, is an ATP-dependent present in all kingdoms of life. It involved protein quality control and several regulatory processes. Eukaryotic Lon possesses three domains, N-terminal domain, ATPase domain a proteolytic domain. requires ATP hydrolysis to digest larger, intact proteins, but can cleave small, fluorogenic peptides such as Glu-Ala-Ala-Phe-MNA by only binding, not hydrolyzing, ATP. Both peptidase activities be stimulated the binding larger substrate, β-casein. To better understand its mechanism action, we have prepared point mutants four conserved residues human (G893A, G893P, G894A, G894P, G894S, G893A-G894A, G893P-G894A, G893A-G894P, T880V, W770A, W770P) studied their ATPase, activities. Our results show that mutations Gly894 enhance basal activity do change β-casein-stimulated activity. The loop containing Gly893 Gly894, which flanks Lon's active site, therefore appears conformational occurs upon substrate binding. Furthermore, Trp770 same general effects on Gly893, indicating stimulation. We established this does need move order peptides, during digestion Finally, noted ability small inhibited moderate concentrations.Lon (Endopeptidase La), EC 4.4.21.53 STRUCTURED DIGITAL ABSTRACT: • hLonP cleaves beta casein assay (1, 2, 3, 4, 5, 6) hLon bind cross-linking study (View interaction).