Kisko Kaisa, Szilvay Géza R, Vainio Ulla, Linder Markus B, Serimaa Ritva
Department of Physical Sciences, University of Helsinki, FI-00014 HU, Finland.
Biophys J. 2008 Jan 1;94(1):198-206. doi: 10.1529/biophysj.107.112359. Epub 2007 Sep 7.
Hydrophobins are a group of very surface-active, fungal proteins known to self-assemble on various hydrophobic/hydrophilic interfaces. The self-assembled films coat fungal structures and mediate their attachment to surfaces. Hydrophobins are also soluble in water. Here, the association of hydrophobins HFBI and HFBII from Trichoderma reesei in aqueous solution was studied using small-angle x-ray scattering. Both HFBI and HFBII exist mainly as tetramers in solution in the concentration range 0.5-10 mg/ml. The assemblies of HFBII dissociate more easily than those of HFBI, which can tolerate changes of pH from 3 to 9 and temperatures in the range 5 degrees C-60 degrees C. The self-association of HFBI and HFBII is mainly driven by the hydrophobic effect, and addition of salts along the Hofmeister series promotes the formation of larger assemblies, whereas ethanol breaks the tetramers into monomers. The possibility that the oligomers in solution form the building blocks of the self-assembled film at the air/water interface is discussed.
疏水蛋白是一类具有很强表面活性的真菌蛋白，已知它们能在各种疏水/亲水界面上自组装。自组装膜覆盖真菌结构并介导其与表面的附着。疏水蛋白也可溶于水。在此，利用小角X射线散射研究了里氏木霉的疏水蛋白HFBI和HFBII在水溶液中的缔合情况。在0.5 - 10 mg/ml的浓度范围内，HFBI和HFBII在溶液中主要以四聚体形式存在。HFBII的聚集体比HFBI的更容易解离，HFBI能耐受pH值从3到9以及温度在5摄氏度至60摄氏度范围内的变化。HFBI和HFBII的自缔合主要由疏水效应驱动，沿着霍夫迈斯特序列添加盐会促进形成更大的聚集体，而乙醇会将四聚体分解成单体。本文还讨论了溶液中的寡聚体在空气/水界面形成自组装膜结构单元的可能性。
