Structure and thermal stability of the extracellular fragment of human transferrin receptor at extracellular and endosomal pH

FEBS Letters

Srai, Surjit K.S.²  Chapman, Dennis²  Hadden, Jonathan M.²  Haris, Parvez I.²  Bloemendal, Michael²  van Stokkum, Ivo H.M.¹ 

[1]Faculty of Physics and Astronomy, Free University, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands

[2]Department of Protein and Molecular Biology, The Royal Free Hospital School of Medicine, Rowland Hill Street, London, NW3 2PF, UK

关键词: Fourier transform infrared spectroscopy;    Secondary structure;    Tertiary structure;    Thermal stability;    pH-dependent conformational change;    CD;    circular dichroism;    FTIR;    Fourier transform infrared spectroscopy;    HEPES;    (N-[2-hydroxyethyl]piperazine-N′-[2-ethanesulp honic acid]);    MES;    (2-[N-morpholino]ethanesulfonic acid);    SDS-PAGE;    sodium dodecylsulphate polyacrylamide gel electrophoresis;    tfR;    human placental transferrin receptor;    tfRt;    trypsin cleavable fragment of human placental transferrin receptor;   

DOI  :  10.1016/0014-5793(94)00774-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Fourier transform infrared spectroscopy has been used to study the solution structure and thermal stability of the extracellular fragment of human transferrin receptor (tfRt) at extracellular and endosomal pH. At extracellular pH tfRt is composed of 56% α-helix, 19% β-sheet and 14% turns. Upon acidification to endosomal pH the α-helical content of the protein is reduced and the β-sheet content increased by nearly 10%. At extracellular pH, the midpoint temperature of thermal denaturation (T _m) for the loss of secondary and tertiary structure, and the formation of aggregated structures, is 71°C. At endosomal pH this temperature is reduced by ≈ 15°C. The apparent entropies of thermal denaturation indicate that the native structure of tfRt at endosomal pH is far more flexible than at extracellular pH.

【 授权许可】

Unknown