RESUMEN
The intrinsically disordered protein α-synuclein plays a major role in Parkinson's disease. The protein can oligomerize resulting in the formation of various aggregated species in neuronal cells, leading to neurodegeneration. The interaction of α-synuclein with biological cell membranes plays an important role for specific functions of α-synuclein monomers, e.g., in neurotransmitter release. Using different types of detergents to mimic lipid molecules present in biological membranes, including the presence of Ca2+ ions as an important structural factor, we aimed to gain an understanding of how α-synuclein interacts with membrane models and how this affects the protein conformation and potential oligomerization. We investigated detergent binding stoichiometry, affinity and conformational changes of α-synuclein taking detergent concentration, different detergent structures and charges into account. With native nano-electrospray ionization ion mobility-mass spectrometry, we were able to detect unique conformational patterns resulting from binding of specific detergents to α-synuclein. Our data demonstrate that α-synuclein monomers can interact with detergent molecules irrespective of their charge, that protein-micelle interactions occur and that micelle properties are an important factor.
Asunto(s)
Detergentes/farmacología , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo , Humanos , Modelos Biológicos , Modelos Moleculares , Nanotecnología , Unión Proteica , Conformación Proteica , Multimerización de Proteína , Espectrometría de Masa por Ionización de Electrospray , alfa-Sinucleína/efectos de los fármacosRESUMEN
Biomedicinally important histone lysine methyltransferases (KMTs) transfer a methyl group from S-adenosylmethionine to lysine residues in histones and other proteins. Here, we report comparative studies on epigenetic methylation of lysine and γ-thialysine, the simplest cysteine-derived lysine analog, which can be introduced to histone peptides and histone proteins via site-specific bioconjugation-based cysteine alkylation. Enzyme assays and computational studies demonstrate that human KMTs catalyze efficient methylation of histones that possess γ-thialysine. This work provides a molecular basis for the application of γ-thialysine for biomolecular studies of intact histones and the nucleosome assembly.