Universal open MHC-I molecules for rapid peptide loading and enhanced complex stability across HLA allotypes.
Universal open MHC-I molecules for rapid peptide loading and enhanced complex stability across HLA allotypes.
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DOI：
10.1073/pnas.2304055120
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发表时间：
2023-06-20
影响因子：
11.1
通讯作者：
Sgourakis, Nikolaos G.
中科院分区：
文献类型：
--
作者：
Sun, Yi;Young, Michael C.;Woodward, Claire H.;Danon, Julia N.;Truong, Hau, V;Gupta, Sagar;Winters, Trenton J.;Font-Burgada, Joan;Burslem, George M.;Sgourakis, Nikolaos G.
关键词：
我们概述了一种结构导向的方法，用于生成构象稳定，开放的MHC-I，具有增强的配体交换动力学，跨越五种HLA-A超型，所有HLA-B超型和寡形HLA-Ib同种异型。我们提出了直接证据表明肽结合和β2m与重链结合之间存在正的变构协同作用。我们证明共价连接的β2m作为构象伴侣，通过促进开放构象和防止本质上不稳定的异二聚体不可逆聚集，使空MHC-I分子稳定在肽接受状态。我们的研究为MHC-I三元配合物的构象特性提供了结构和生物物理方面的见解，改进了超稳定、通用配体交换系统的设计，并为在泛hla等位基因环境中表征抗病原体、肿瘤或自身免疫相关肽表位的tcr提供了工具。一类主要组织相容性复合体（MHC-I）和mhc样分子装载的次优肽、代谢物或糖脂质具有多态性和内在不稳定性，这对识别疾病相关抗原和抗原特异性T细胞受体（TCRs）提出了根本性挑战，阻碍了自体治疗的发展。在这里，我们利用肽和轻链（β2微球蛋白，β2m）亚基之间的正变构偶联，通过工程二硫键桥接HC/β2m界面上的保守表位，与MHC-I重链（HC）结合，生成构象稳定的肽受体分子，称为“开放MHC-I”。生物物理特性表明，与野生型相比，当装载低至中等亲和力肽时，开放的mhc - 1分子是适当折叠的蛋白质复合物，具有增强的热稳定性。利用溶液核磁共振，我们表征了二硫键对MHC-I结构构象和动力学的影响，从肽结合槽β2 - m相互作用位点的局部变化到α2-1螺旋和α3结构域的长期影响。链间二硫键稳定MHC-I分子的开放构象，促进多种人类白细胞抗原（HLA）同种异体之间的肽交换，包括5种HLA- a超型，6种HLA- b超型和寡形HLA- ib分子的代表。我们的结构导向设计与条件β-肽配体相结合，提供了一个通用平台，以生成稳定性增强的准备加载MHC-I系统，使一系列方法能够筛选抗原表位文库和探测覆盖高度多态性HLA-I同种异体的多克隆TCR库，以及寡晶非经典分子。
We outline a structure-guided approach for generating conformationally stable, open MHC-I with enhanced ligand exchange kinetics spanning five HLA-A supertypes, all HLA-B supertypes, and oligomorphic HLA-Ib allotypes. We present direct evidence of positive allosteric cooperativity between peptide binding and β2m association with the heavy chain. We demonstrate that covalently linked β2m serves as a conformational chaperone to stabilize empty MHC-I molecules in a peptide-receptive state, by promoting an open conformation and preventing intrinsically unstable heterodimers from irreversible aggregation. Our study provides structural and biophysical insights into the conformational properties of MHC-I ternary complexes, improving the design of ultrastable, universal ligand exchange systems and the tool for characterizing TCRs against pathogen-, tumor-, or autoimmune-associated peptide epitopes in a pan-HLA allelic setting. The polymorphic nature and intrinsic instability of class I major histocompatibility complex (MHC-I) and MHC-like molecules loaded with suboptimal peptides, metabolites, or glycolipids presents a fundamental challenge for identifying disease-relevant antigens and antigen-specific T cell receptors (TCRs), hindering the development of autologous therapeutics. Here, we leverage the positive allosteric coupling between the peptide and light chain (β2 microglobulin, β2m) subunits for binding to the MHC-I heavy chain (HC) through an engineered disulfide bond bridging conserved epitopes across the HC/β2m interface, to generate conformationally stable, peptide-receptive molecules named “open MHC-I.” Biophysical characterization shows that open MHC-I molecules are properly folded protein complexes of enhanced thermal stability compared to the wild type when loaded with low- to moderate-affinity peptides. Using solution NMR, we characterize the effects of the disulfide bond on the conformation and dynamics of the MHC-I structure, ranging from local changes in β2m-interacting sites of the peptide-binding groove to long-range effects on the α2-1 helix and α3 domain. The interchain disulfide bond stabilizes MHC-I molecules in an open conformation to promote peptide exchange across multiple human leukocyte antigen (HLA) allotypes, covering representatives from five HLA-A supertypes, six HLA-B supertypes, and oligomorphic HLA-Ib molecules. Our structure-guided design, combined with conditional β-peptide ligands, provides a universal platform to generate ready-to-load MHC-I systems of enhanced stability, enabling a range of approaches to screen antigenic epitope libraries and probe polyclonal TCR repertoires covering highly polymorphic HLA-I allotypes, as well as oligomorphic nonclassical molecules.
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影响因子：
14.9
作者：
Barker, Dominic J.;Maccari, Giuseppe;Georgiou, Xenia;Cooper, Michael A.;Flicek, Paul;Robinson, James;Marsh, Steven G. E.
通讯作者：
Marsh, Steven G. E.
影响因子：
7.7
作者：
Hermann, Clemens;van Hateren, Andy;Boyle, Louise H.
通讯作者：
Boyle, Louise H.
影响因子：
56.9
作者：
Altman, JD;Moss, PAH;Davis, MM
通讯作者：
Davis, MM
DOI：
10.1073/pnas.1809465115
发表时间：
2018-10-02
影响因子：
11.1
作者：
Ilca, F. Tudor;Neerincx, Andreas;Boyle, Louise H.
通讯作者：
Boyle, Louise H.
影响因子：
29.7
作者：
Blum JS;Wearsch PA;Cresswell P
通讯作者：
Cresswell P