Pinter A, Kopelman R, Li Z, Kayman S C, Sanders D A
Public Health Research Institute, and Department of Microbiology, New York University School of Medicine, New York 10016, USA.
J Virol. 1997 Oct;71(10):8073-7. doi: 10.1128/JVI.71.10.8073-8077.1997.
Previous studies have indicated that the surface (SU) and transmembrane (TM) subunits of the envelope protein (Env) of murine leukemia viruses (MuLVs) are joined by a labile disulfide bond that can be stabilized by treatment of virions with thiol-specific reagents. In the present study this observation was extended to the Envs of additional classes of MuLV, and the cysteines of SU involved in this linkage were mapped by proteolytic fragmentation analyses to the CWLC sequence present at the beginning of the C-terminal domain of SU. This sequence is highly conserved across a broad range of distantly related retroviruses and resembles the CXXC motif present at the active site of thiol-disulfide exchange enzymes. A model is proposed in which rearrangements of the SU-TM intersubunit disulfide linkage, mediated by the CWLC sequence, play roles in the assembly and function of the Env complex.
先前的研究表明,鼠白血病病毒(MuLVs)包膜蛋白(Env)的表面(SU)亚基和跨膜(TM)亚基通过一个不稳定的二硫键相连,该二硫键可通过用硫醇特异性试剂处理病毒粒子来稳定。在本研究中,这一观察结果扩展到了其他类别的MuLV的Env,并且通过蛋白水解片段分析将参与此连接的SU中的半胱氨酸定位到SU C末端结构域起始处的CWLC序列。该序列在广泛的远缘逆转录病毒中高度保守,并且类似于硫醇 - 二硫键交换酶活性位点处存在的CXXC基序。提出了一个模型,其中由CWLC序列介导的SU - TM亚基间二硫键连接的重排在Env复合物的组装和功能中发挥作用。