Vera Andrés Manuel, Galera-Prat Albert, Wojciechowski Michał, Różycki Bartosz, Laurents Douglas V, Carrión-Vázquez Mariano, Cieplak Marek, Tinnefeld Philip
Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13 Haus E, 81377 München, Germany.
Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90014 Oulu, Finland.
Structure. 2021 Jun 3;29(6):587-597.e8. doi: 10.1016/j.str.2021.01.006. Epub 2021 Feb 8.
Cellulose is the most abundant organic molecule on Earth and represents a renewable and practically everlasting feedstock for the production of biofuels and chemicals. Self-assembled owing to the high-affinity cohesin-dockerin interaction, cellulosomes are huge multi-enzyme complexes with unmatched efficiency in the degradation of recalcitrant lignocellulosic substrates. The recruitment of diverse dockerin-borne enzymes into a multicohesin protein scaffold dictates the three-dimensional layout of the complex, and interestingly two alternative binding modes have been proposed. Using single-molecule fluorescence resonance energy transfer and molecular simulations on a range of cohesin-dockerin pairs, we directly detect varying distributions between these binding modes that follow a built-in cohesin-dockerin code. Surprisingly, we uncover a prolyl isomerase-modulated allosteric control mechanism, mediated by the isomerization state of a single proline residue, which regulates the distribution and kinetics of binding modes. Overall, our data provide a novel mechanistic understanding of the structural plasticity and dynamics of cellulosomes.
纤维素是地球上最丰富的有机分子，是生产生物燃料和化学品的可再生且几乎取之不尽的原料。由于高亲和力的黏连蛋白-锚定蛋白相互作用而自组装，纤维小体是巨大的多酶复合物，在降解顽固的木质纤维素底物方面具有无与伦比的效率。将多种锚定蛋白携带的酶招募到多黏连蛋白蛋白质支架中决定了复合物的三维布局，有趣的是，已经提出了两种替代结合模式。通过对一系列黏连蛋白-锚定蛋白对进行单分子荧光共振能量转移和分子模拟，我们直接检测到这些结合模式之间不同的分布，这些分布遵循内在的黏连蛋白-锚定蛋白编码。令人惊讶的是，我们发现了一种脯氨酰异构酶调节的变构控制机制，由单个脯氨酸残基的异构化状态介导，该机制调节结合模式的分布和动力学。总体而言，我们的数据为纤维小体的结构可塑性和动力学提供了新的机制理解。
