Cooper P G, Carver J A, Truscott R J
Australian Cataract Research Foundation, Department of Chemistry, University of Wollongong.
Eur J Biochem. 1993 Apr 1;213(1):321-8. doi: 10.1111/j.1432-1033.1993.tb17765.x.
1H-NMR spectroscopic studies of bovine eye lens beta-crystallin aggregates (dimer, trimer and octomer) are presented. The NMR spectra for all three beta-crystallin aggregates are dominated by resonances from the beta B2 subunit, particularly from the N- and C-terminal extensions of this subunit. Resonances from other beta subunits, which all have terminal extensions, are, in general, absent from spectra of the beta-crystallin aggregates. Therefore, the beta B2 subunit and, in particular its terminal extensions, has enhanced flexibility compared to the other beta-crystallin subunits. Furthermore, resonances arising from the C-terminal extension of beta B2-crystallin are not present in the spectrum of the octomer, which is consistent with the C-terminal extension binding in this aggregate and hence being involved in large aggregate formation. A possible interaction between the C-terminal extension of beta B2 and the hydrophobic beta B1 subunit, which is only found in the octomer, is discussed. At higher temperatures (45 degrees C) in the octomer, partial exposure of the C-terminal extension of beta B2 occurs indicating that the octomer may be starting to break up into smaller aggregates.
本文介绍了牛眼晶状体β-晶状体蛋白聚集体（二聚体、三聚体和八聚体）的1H-NMR光谱研究。所有三种β-晶状体蛋白聚集体的NMR光谱均以βB2亚基的共振为主，特别是该亚基的N端和C端延伸部分。来自其他β亚基（均有末端延伸）的共振通常在β-晶状体蛋白聚集体的光谱中不存在。因此，与其他β-晶状体蛋白亚基相比，βB2亚基，特别是其末端延伸部分，具有更高的灵活性。此外，βB2-晶状体蛋白C端延伸产生的共振在八聚体的光谱中不存在，这与该聚集体中C端延伸的结合情况一致，因此参与了大聚集体的形成。本文还讨论了βB2的C端延伸与仅在八聚体中发现的疏水βB1亚基之间可能存在的相互作用。在八聚体中，温度较高（45摄氏度）时，βB2的C端延伸会部分暴露，这表明八聚体可能开始分解为较小的聚集体。
