Secondary structure, stability and tetramerisation of recombinant K_V1.1 potassium channel cytoplasmic N-terminal fragment

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• 作者：Abbott ; Geoffrey W. ; Bloemendal ; Michael ; Van Stokkum ; Ivo H.M. ; Mercer ; Eric A.J. ; Miller ; Rob T. ; et. al.
• 关键词：Fourier transform infrared spectroscopy ; Circular dichroism spectroscopy ; Secondary structure ; Tertiary structure ; Thermal stability ; Tetramerisation ; AA ; amino acids ; CMC ; critical micellisation concentration ; DTT ; dithiothreitol ; FTIR ; Fourier-transform
• 刊名：Biochimica et Biophysica Acta (BBA)/Protein Structure and Molecular Enzymology
• 出版年：1997
• 出版时间：August 15, 1997
• 年：1997
• 卷：1341
• 期：1
• 页码：71-78
• 全文大小：693 K

文摘

The recombinant N-terminal fragment (amino acids 14-162) of a tetrameric voltage-gated potassium channel (K_V1.1) has been studied using spectroscopic techniques. Evidence is presented that it forms a tetramer in aqueous solution, whereas when solubilised in 1 % Triton X-100 it remains monomeric. The secondary structure content of both monomeric and tetrameric K_V1.1 N-terminal fragment has been estimated from FTIR and CD spectroscopy to be 20–25 % α-helix, 20–25 % β-sheet, 20 % turns and 30–40 % random coil. Solubilisation of the protein in detergent is shown by hydrogen-deuterium exchange analysis to alter tertiary structure rather than secondary structure and this may be the determining factor in tetramerisation ability. Using molecular modelling we propose a supersecondary structure consisting of two structural domains.