Department of Physics and Astronomy, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78242, USA.
Int J Biol Macromol. 2013 Feb;53:42-53. doi: 10.1016/j.ijbiomac.2012.10.030. Epub 2012 Nov 10.
The manuscript describes the study of the oligomerization process of bovine serum albumin (BSA) in two different structural monomeric forms: the extended-form (E) at pH 2.0 and the basic-form (B) at pH 9.0. The study was conducted at low protein concentration (1mg/ml) and relatively short incubation time (maximum 56 days) in order to investigate early oligomerization events rather than the formation of mature fibrils. The comparison between the two isoforms show that oligomers form much faster (∼6 days) in the E-form than in the B-form where formation of oligomers requires ∼4 weeks. The oligomers appear to be limited to a maximum of tetramers with size <30 nm. Hydrophobic interactions from exposed neutral amino acid residues in the elongated E-form are the likely cause for the quick formation of aggregates at acidic pH. We used an array of biophysical techniques for the study and determined that oligomerization occurs without further large changes in the secondary structure of the monomers. Under the conditions adopted in this study, aggregation does not seem to exceed the formation of tetramers, even though a very small amount of much larger aggregates seem to form.
该手稿描述了牛血清白蛋白（BSA）在两种不同结构单体形式中的寡聚化过程研究：在 pH 值为 2.0 时的伸展形式（E 形式）和在 pH 值为 9.0 时的碱性形式（B 形式）。研究在低蛋白浓度（1mg/ml）和相对较短的孵育时间（最长 56 天）下进行，目的是研究早期寡聚化事件，而不是成熟纤维的形成。两种形式的比较表明，E 形式中的寡聚物形成速度更快（约 6 天），而 B 形式中寡聚物的形成则需要约 4 周。寡聚物似乎仅限于大小<30nm 的最大四聚体。在酸性 pH 下，伸展的 E 形式中暴露的中性氨基酸残基的疏水力可能是快速形成聚集体的原因。我们使用了一系列生物物理技术进行研究，并确定寡聚化发生时，单体的二级结构没有进一步的大变化。在本研究中采用的条件下，聚集似乎不会超过四聚体的形成，尽管似乎形成了非常少量的更大聚集体。
