Latent membrane protein 1 (LMP1) is a gene product of the Epstein-Barr virus (EBV), a widely spread virus present in 90–95% of the world's population. EBV can lead to several malignancies, in which LMP1 was shown to play a key role. LMP1 is active only in the oligomeric form and its fifth transmembrane domain (TMD-5) is critical for the oligomerization, with D150 identified as a key residue for LMP1 activation. Here we propose an NMR-based approach to treat the complex oligomerization equilibria with slow conformational exchange. Using this method we investigate the TMD-5 in DPC micelles. We show that the pKa of D150 equals 7.4. Uncharged form of TMD-5 associates into dimers and trimers, deprotonation of D150 induces the high-order oligomerization of the protein and enhances dramatically its trimerization. Pentamidine interacts mainly with the charged TMD-5, destroying the oligomers and stabilizing the monomer and trimer. Using computer simulations we investigate the structural basis of TMD-5/pentamidine interaction. Our data suggest that D150 is likely charged in the full-length LMP1 under native conditions.

潜在膜蛋白1（LMP1）是爱泼斯坦-巴尔病毒（EBV）的基因产物，该病毒在世界90-95％的人口中广泛传播。EBV可导致多种恶性肿瘤，其中LMP1被证明发挥关键作用。LMP1仅在寡聚形式下具有活性，其第五个跨膜结构域（TMD-5）对于寡聚化至关重要，其中D150被确定为LMP1激活的关键残基。在这里，我们提出了一种基于核磁共振的方法，以缓慢的构象交换来处理复杂的低聚平衡。使用这种方法，我们研究了DPC胶束中的TMD-5。我们证明D150的pKa等于7.4。TMD-5的不带电荷形式缔合成二聚体和三聚体，D150的去质子化诱导了蛋白质的高级低聚，并显着增强了其三聚化。喷他idine主要与带电的TMD-5相互作用，破坏低聚物并稳定单体和三聚体。使用计算机模拟，我们研究了TMD-5 /戊am相互作用的结构基础。我们的数据表明，在自然条件下，全长LMP1中可能会对D150充电。