Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
Biochemistry (Mosc). 2010 Oct;75(10):1258-63. doi: 10.1134/s000629791010007x.
In the present study, pathways of growth of protein structures represented in the structural tree for β-proteins containing 3β-corners are analyzed. It is shown that the frequency of occurrence of the completed structures of known proteins within branches of the tree is quite different. This means that allowed pathways of growth of protein structures are not equal and their usage is quite different. In most cases, addition of one or two β-strands nearest along the chain to the root 3β-corner (67%) or addition of three β-strands to the 3β-corner results in the formation of structures closed into cycles or barrels. Therefore, the pathways that result in closed structures are used most often in the first steps of growth of the root 3β-corner. Amino acid sequences coding for left-handed superhelices that close into cycles the 3β-corners are also analyzed. It is demonstrated that most crossover sites where the polypeptide chain passes from one β-layer to the other have one or two residues in sterically constrained α(L)- or ε-conformations, which should be glycines or residues with flexible side chains in order to reduce the steric constraints.
在本研究中，分析了包含 3β-转角的β-蛋白结构树中所表示的蛋白质结构生长途径。结果表明，树中分支内出现的已知蛋白质完整结构的频率差异很大。这意味着允许的蛋白质结构生长途径并不均等，其使用也有很大差异。在大多数情况下，向根 3β-转角添加一个或两个沿链最近的β-链（67%），或者向 3β-转角添加三个β-链，会导致形成封闭的环或桶状结构。因此，在根 3β-转角生长的最初步骤中，最常使用导致封闭结构的途径。还分析了编码封闭 3β-转角的左手超螺旋的氨基酸序列。结果表明，多肽链从一个β-层转移到另一个β-层的交叉点大多位于空间受限的α(L)-或ε-构象中的一个或两个残基上，这些残基应该是甘氨酸或具有柔性侧链的残基，以减少空间限制。
