来自生化和分子生物学实验的综合信息揭示了一致的结构节奏,这是所有膜载体以及可能所有转运系统构建的基础。生化工作表明,虽然一些载体蛋白作为单体,其他人作为二聚体操作。但是尽管有这种变化,所有示例都可以建模为具有一对膜嵌入域,每一个包含(约)六个跨膜螺旋元件的阵列。这种模式最好记录在膜载体中,在合理数量的情况下,最小功能单元是已知的。然而,同样的结论很可能是其他溶质转运蛋白的特征。这些意想不到的相关性表明,所有的膜载体,包括那些参与“能量耦合”的人,具有统一的结构设计,叠加了各种动力学和生化机制。
Combined information from biochemical and molecular biological experiments reveals a consistent structural rhythm that underlies the construction of all membrane carriers and perhaps all transport systems. Biochemical work shows that while some carrier proteins function as monomers, others operate as dimers. But despite this variation, all examples can be modelled as having a pair of membrane-embedded domains, each of which contains an array of (about) six transmembrane helical elements. This pattern is best documented among membrane carriers, where the minimal functional unit is known in a reasonable number of cases. Nevertheless, the same conclusion is likely to characterize other solute transporters. These unexpected correlations suggest that all membrane carriers, including those that take part in \"energy coupling\", have a uniform structural design on which is superimposed a variety of kinetic and biochemical mechanisms.