title: Optimal cleavage and oxidative folding of α-conotoxin TxIB as a therapeutic candidate peptide.
abstract: Alpha6beta2 nicotinic acetylcholine receptors (nAChRs) are potential therapeutic targets for the treatment of several neuropsychiatric diseases, including addiction and Parkinson's disease. Alpha-conotoxin (α-CTx) TxIB is a uniquely selective ligand, which blocks α6/α3β2β3 nAChRs only, but does not block the other subtypes. Therefore, α-CTx TxIB is a valuable therapeutic candidate peptide. Synthesizing enough α-CTx TxIB with high yield production is required for conducting wide-range testing of its potential medicinal applications. The current study optimized the cleavage of synthesized α-CTx TxIB resin-bounded peptide and folding of the cleaved linear peptide. Key parameters influencing cleavage and oxidative folding of α-CTx TxIB were examined, such as buffer, redox agents, pH, salt, co-solvent and temperature. Twelve conditions were used for cleavage optimization. Fifty-four kinds of one-step oxidative solution were used to assess their effects on each α-CTx TxIB isomers' yield. The result indicated that co-solvent choices were particularly important. Completely oxidative folding of globular isomer was achieved when the NH₄HCO₃ or Tris-HCl folding buffer at 4 °C contained 40% of co-solvent DMSO, and GSH:GSSG (2:1) or GSH only with pH 8~8.7.
authors.affiliation: Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drug of Haikou, Hainan University, Haikou, Hainan 570228, China.
authors.forename: Xiaosa
authors.initials: X
authors.lastname: Wu
authors.forename: Yong
authors.initials: Y
authors.lastname: Wu
authors.forename: Furong
authors.initials: F
authors.lastname: Zhu
authors.forename: Qiuyuan
authors.initials: Q
authors.lastname: Yang
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Wu
authors.forename: Dongting
authors.initials: D
authors.lastname: Zhangsun
authors.forename: Sulan
authors.initials: S
authors.lastname: Luo
mesh_terms: D020916:Conotoxins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010455:Peptides / Q000378:metabolism*; D017510:Protein Folding; D012492:Salts / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013696:Temperature
chemical_list: D020916:Conotoxins; D010455:Peptides; D012492:Salts; D012996:Solutions; D012997:Solvents
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