Andreeva Antonina, Murzin Alexey G
MRC Centre for Protein Engineering, Hills Road, Cambridge CB2 2QH, UK.
Curr Opin Struct Biol. 2006 Jun;16(3):399-408. doi: 10.1016/j.sbi.2006.04.003. Epub 2006 May 2.
The functional requirement to form and maintain the active site structure probably exerts a strong selective pressure on a protein to adopt just one stable and evolutionarily conserved fold. Nonetheless, new evidence suggests the likelihood of protein fold being neither physically nor biologically invariant. Alternative folds discovered in several proteins are composed of constant and variable parts. The latter display context-dependent conformations and a tendency to form new oligomeric interfaces. In turn, oligomerisation mediates fold evolution without loss of protein function. Gene duplication breaks down homo-oligomeric symmetry and relieves the pressure to maintain the local architecture of redundant active sites; this can lead to further structural changes.
形成并维持活性位点结构的功能需求可能会对蛋白质施加强大的选择压力，使其仅采用一种稳定且在进化上保守的折叠方式。然而，新证据表明蛋白质折叠在物理和生物学上都并非一成不变。在几种蛋白质中发现的替代折叠由恒定部分和可变部分组成。后者呈现出依赖于上下文的构象，并倾向于形成新的寡聚界面。反过来，寡聚化介导折叠进化而不丧失蛋白质功能。基因复制打破了同寡聚体对称性，并减轻了维持冗余活性位点局部结构的压力；这可能导致进一步的结构变化。
