Evidence for Self-Association of a Miniaturized Version of Agrin from Hydrodynamic and Small-Angle X-ray Scattering Measurements

详细信息    查看全文

• 作者：Trushar R. Patel ; Tabot M. D. Besong ; Nehal Patel ; Markus Meier ; Stephen E. Harding ; Donald J. Winzor ; Jo虉rg Stetefeld
• 刊名：Journal of Physical Chemistry B
• 出版年：2011
• 出版时间：September 29, 2011
• 年：2011
• 卷：115
• 期：38
• 页码：11286-11293
• 全文大小：902K
• 年卷期：v.115,no.38(September 29, 2011)
• ISSN：1520-5207

文摘

Hydrodynamic studies of miniagrin indicate a molar mass that is 20% larger than the value calculated from the sequence of this genetically engineered protein. Consistent with this finding is the negative sign and also the magnitude of the second virial coefficient obtained from small-angle X-ray scattering measurements. The inference that miniagrin reversibly self-associates is confirmed by a sedimentation equilibrium study that yields an equilibrium constant of 0.24 L/g for a putative monomer鈥揹imer interaction. Finally, Guinier analysis of the small-angle X-ray scattering (SAXS) results yields concentration-dependent values for the radius of gyration that may be described by the monomer鈥揹imer model and respective R_g values of 40 and 105 脜 for the monomeric and dimeric miniagrin species. Although intermolecular protein interactions are endemic in the events leading to acetylcholine receptor aggregation by agrin, the matrix proteoglycan of which miniagrin is a miniaturized model, this investigation raises the possibility that agrin may itself self-associate.