Tandem mass spectrometry defines the stoichiometry and quaternary structural arrangement of tryptophan molecules in the multiprotein complex TRAP
Tandem mass spectrometry defines the stoichiometry and quaternary structural arrangement of tryptophan molecules in the multiprotein complex TRAP
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DOI：
10.1021/ja0317170
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发表时间：
2004-05-19
影响因子：
15
通讯作者：
Robinson, CV
中科院分区：
文献类型：
--
作者：
McCammon, MG;Hernández, H;Robinson, CV
我们已经使用串联质谱检查的化学计量和结合位点的色氨酸分子在各种组装的蛋白质复合物TRAP。结果表明，TRAP形成含有11和12个亚基的寡聚体。MS/MS实验表明，多达11个色氨酸分子结合的12聚体，但在气相解离5，然后6色氨酸分子被释放，反映不同的气相稳定性的部分连接的形式。在高浓度的色氨酸，蛋白质组装形成一个双环结构。串联质谱显示它由24个亚基和多达22个色氨酸分子组成。的复合物的解离揭示了相同的解离途径，为单环结构，使我们能够提出一个模型的TRAP 24聚体的组装的基础上的色氨酸分子的不同环境。更一般地说，这些结果证明了串联质谱的权力，用于定义的化学计量和四级结构的安排，在一个46组分的多蛋白质多配体复合物的亚基和配体。
We have used tandem mass spectrometry to examine the stoichiometry and binding sites of trp molecules in various assemblies of the protein complex TRAP. The results show that TRAP forms oligomers containing 11 and 12 subunits. MS/MS experiments show that up to 11 trp molecules bind to the 12-mer but that during gas-phase dissociation 5 then 6 trp molecules are released reflecting the different gas-phase stabilities of the partially ligated forms. At high trp concentrations, the protein assembles to form a double ring structure. Tandem mass spectrometry reveals that it is composed of 24 subunits with up to 22 molecules of trp. Dissociation of the complex reveals the same dissociation pathway as for the single ring structure, allowing us to propose a model for the assembly of the TRAP 24-mer based on the different environments of trp molecules. More generally, these results demonstrate the power of tandem mass spectrometry for defining the stoichiometry and quaternary structural arrangement of subunits and ligands within a 46-component multiprotein multiligand complex.