from ∼10% to ∼30 %
||Theillet FX et al., Physicochemical properties of cells and their effects on intrinsically disordered proteins (IDPs). Chem Rev. 2014 Jul 9 114(13):6661-714. doi: 10.1021/cr400695p p.6683 left column 2nd paragraphPubMed ID24901537
|| Maltsev AS, Ying J, Bax A. Impact of N-terminal acetylation of α-synuclein on its random coil and lipid binding properties. Biochemistry. 2012 Jun 2651(25):5004-13. doi: 10.1021/bi300642h  Kang L et al., N-terminal acetylation of α-synuclein induces increased transient helical propensity and decreased aggregation rates in the intrinsically disordered monomer. Protein Sci. 2012 Jul21(7):911-7. doi: 10.1002/pro.2088PubMed ID22694188, 22573613
||Primary source  abstract: "N-Terminal acetylation of α-synuclein (aS), a protein implicated in the etiology of Parkinson's disease, is common in mammals. The impact of this modification on the protein's structure and dynamics in free solution and on its membrane binding properties has been evaluated by high-resolution nuclear magnetic resonance and circular dichroism (CD) spectroscopy." Primary source  abstract: "In this work, [investigators] report that recombinant 100% N-terminal acetylated α-synuclein purified under mild physiological conditions presents as a primarily monomeric protein, and that the N-terminal acetyl group affects the transient secondary structure and fibril assembly rates of the protein. Residue-specific NMR [Nuclear magnetic resonance] chemical shift analysis indicates substantial increase in transient helical propensity in the first 9 N-terminal residues, as well as smaller long-range changes in residues 28-31, 43-46, and 50-66: regions in which the three familial mutations currently known to be causative of early onset disease are found."
||P.6683 left column 2nd paragraph: "Recent evidence further suggests that N-terminal acetylation of α-synuclein increases transient helicity from ∼10% to ∼30% (primary sources). In agreement with conformational selection driving the initial membrane encounter, N-terminally acetylated α-synuclein binds membranes with higher affinity than the nonacetylated form of the protein (primary source 505). Thus, arguing that this enzyme-mediated cotranslational protein modification enhances the intrinsic propensity of α-synuclein to interact with physiological membranes."