Roman Ernesto A, González Flecha F Luis
Laboratory of Molecular Biophysics, Institute of Biochemistry and Biophysical Chemistry, University of Buenos Aires-CONICET, Buenos Aires 1113, Argentina.
Biomolecules. 2014 Mar 18;4(1):354-73. doi: 10.3390/biom4010354.
Understanding protein folding has been one of the great challenges in biochemistry and molecular biophysics. Over the past 50 years, many thermodynamic and kinetic studies have been performed addressing the stability of globular proteins. In comparison, advances in the membrane protein folding field lag far behind. Although membrane proteins constitute about a third of the proteins encoded in known genomes, stability studies on membrane proteins have been impaired due to experimental limitations. Furthermore, no systematic experimental strategies are available for folding these biomolecules in vitro. Common denaturing agents such as chaotropes usually do not work on helical membrane proteins, and ionic detergents have been successful denaturants only in few cases. Refolding a membrane protein seems to be a craftsman work, which is relatively straightforward for transmembrane β-barrel proteins but challenging for α-helical membrane proteins. Additional complexities emerge in multidomain membrane proteins, data interpretation being one of the most critical. In this review, we will describe some recent efforts in understanding the folding mechanism of membrane proteins that have been reversibly refolded allowing both thermodynamic and kinetic analysis. This information will be discussed in the context of current paradigms in the protein folding field.
理解蛋白质折叠一直是生物化学和分子生物物理学中的重大挑战之一。在过去的50年里，人们进行了许多热力学和动力学研究，以探讨球状蛋白质的稳定性。相比之下，膜蛋白折叠领域的进展则远远滞后。尽管膜蛋白约占已知基因组编码蛋白质的三分之一，但由于实验限制，对膜蛋白稳定性的研究受到了阻碍。此外，目前还没有用于在体外折叠这些生物分子的系统实验策略。常见的变性剂如离液剂通常对螺旋膜蛋白不起作用，离子去污剂仅在少数情况下是成功的变性剂。重新折叠膜蛋白似乎是一项技术活，对于跨膜β桶蛋白来说相对简单，但对于α螺旋膜蛋白则具有挑战性。多结构域膜蛋白会出现更多复杂情况，数据解读是其中最关键的问题之一。在这篇综述中，我们将描述一些最近在理解膜蛋白折叠机制方面所做的努力，这些膜蛋白已被可逆地重新折叠，从而能够进行热力学和动力学分析。我们将结合蛋白质折叠领域的当前范式来讨论这些信息。
