Rounding up: Engineering 12-membered rings from the cyclic 11-mer TRAP
Rounding up: Engineering 12-membered rings from the cyclic 11-mer TRAP
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DOI：
10.1016/j.str.2006.03.013
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发表时间：
2006-05-01
期刊：
影响因子：
5.7
通讯作者：
Tame, Jeremy R. H.
中科院分区：
文献类型：
--
作者：
Heddle, Jonathan G.;Yokoyama, Takeshi;Tame, Jeremy R. H.
TRAP（trp RNA binding attenuation protein，trp RNA binding attenuation protein）是一种高度耐热的环状11聚体。通过串联连接两个，三个或四个编码TRAP单体的DNA序列，我们设计了由12个TRAP亚基组成的新环，并结合12个配体分子。在11-mer和12-mer晶体结构之间，亚基内和亚基之间的氢键模式和掩埋表面积基本上是相同的。为什么人工蛋白质选择制造单一的12聚体环？12-mer环通过它们的肽接头高度空间紧张，并且远不耐热。蛋白质选择采用几个亚基的应变构象，而不是具有11个亚基的非应变构象，这表明熵因子在控制蛋白质-蛋白质相互作用中的重要性。
The protein TRAP (trp RNA binding attenuation protein) forms a highly thermostable ring-shaped 11-mer. By linking in tandem two, three, or four DNA sequences encoding TRAP monomers, we have engineered new rings that consist of 12 TRAP subunits and bind 12 ligand molecules. The hydrogen bonding pattern and buried surface area within and between subunits are essentially identical between the 11-mer and 12-mer crystal structures. Why do the artificial proteins choose to make single 12-mer rings? The 12-mer rings are highly sterically strained by their peptide linkers and far from thermostable. That proteins choose to adopt a strained conformation of few subunits rather than an unstrained one with 11 subunits demonstrates the importance of entropic factors in controlling protein-protein interactions in general.