Bhattacharjee Pritha, Dasgupta Dipak, Sengupta Kaushik
Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics , 1/AF Bidhannagar, Kolkata-700064, India.
J Phys Chem B. 2015 Nov 5;119(44):14014-21. doi: 10.1021/acs.jpcb.5b07320. Epub 2015 Oct 27.
Lamin B1 is one of the major constituents of the nuclear lamina, a filamentous network underlying the nucleoplasmic side of the inner nuclear membrane. Homopolymerization of lamin B1, coupled to the homotypic and heterotypic association of other lamin types, is central to building the higher order network pattern inside the nucleus. This in turn maintains the mechanical and functional integrity of the lamina. We have characterized the molecular basis of the self-association of lamin B1 using spectroscopic and calorimetric methods. We report that concentration dependent lamin B1 oligomerization involves significant alterations in secondary and tertiary structures of the protein resulting in fairly observable compaction in size. Comparison of the energetics of the homotypic association of lamin B1 with that of lamin A reported earlier led to the finding that lamin A oligomers had higher thermodynamic stability. This leads us to conjecture that lamin B1 has less stress bearing ability compared to lamin A.
核纤层蛋白B1是核纤层的主要成分之一，核纤层是位于内核膜核质侧的丝状网络。核纤层蛋白B1的同聚作用，以及与其他核纤层蛋白类型的同型和异型缔合，对于构建细胞核内的高阶网络模式至关重要。这反过来又维持了核纤层的机械和功能完整性。我们使用光谱和量热法表征了核纤层蛋白B1自缔合的分子基础。我们报告，浓度依赖性的核纤层蛋白B1寡聚化涉及蛋白质二级和三级结构的显著改变，导致大小上相当明显的压缩。将核纤层蛋白B1同型缔合的能量学与先前报道的核纤层蛋白A的能量学进行比较，发现核纤层蛋白A寡聚物具有更高的热力学稳定性。这使我们推测，与核纤层蛋白A相比，核纤层蛋白B1的应力承受能力较低。
