被MHC I类分子捕获的脂联体经历了动态的构造变化,影响了它们的抗原强度
Daisuke Morita1, Toshiki Fujii2, Shinsuke Inuki3
1Laboratory of Cell Regulation, Institute for Life and Medical Sciences, Kyoto University, Kyoto, Japan.
The Journal of biological chemistry
|December 14, 2025
概括
主要组织相容性复合体I类蛋白质存在N-myristoylated脂. 这项研究揭示了脂形状决定了T细胞受体结合和抗原强度,解释了相似的表位素如何引起不同的免疫反应.
科学领域:
- 免疫学 免疫学 免疫学
- 结构生物学 结构生物学
- 生物化学 生化学
背景情况:
- 主体自身相容性复合体 (MHC) I类分子向T细胞呈现,通常是较长的.
- 一个MHCI类分子的子集可以呈现N-myristoylated短脂,如那些来自逆转录病毒Nef蛋白.
- 相互作用涉及特定的MHC I类异构体,如Mamu-B*05104,和T细胞受体 (TCR).
研究的目的:
- 阐明控制N-myristoylated lipopeptides抗原强度的分子机制.
- 了解为什么共享主要T细胞表皮质的脂可以是抗原性或非抗原性.
- 为了研究差异性T细胞对脂抗原的识别的结构基础.
主要方法:
- 使用了N-myristoylated 4-mer lipopeptides (C14nef4) 和它们的类似物与氨基酸替代物.
- 采用生物层干扰测量来测量固定TCR和Mamu-B*05104-脂复合体之间的结合亲和力.
- 确定了Mamu-B*05104与各种脂复合的晶体结构,并进行了分子动力学模拟.
主要成果:
- C14nef4的myristic酸和C端残留物都在MHC结合中,暴露了像Gly1.1这样的内部残留物.
- Gly1的胺键作为T细胞的主要表位体,但其可访问性各不相同.
- 抗原性较差的脂类型呈现出碳化合物链和Gly1的向下转移,减少了表位暴露.
- 分子动力学模拟证实,脂形状动态影响Gly1表位的外部呈现.
结论:
- N-myristoylated lipopeptides的抗原强度是由它们的内在形状灵活性决定的.
- 保持暴露的T细胞表皮形状的脂具有更高的抗原性.
- 这种形状可塑性解释了具有共享T细胞表位的脂的差异性免疫识别.
相关概念视频
Antigen Processing Pathways
2.0K
MHC molecules are key players in the immune response, enabling T cells to recognize and respond to specific antigens. They are present on the surface of all nucleated cells in the body and are instrumental in presenting antigens to T cells and activating them. T cells recognize the MHC-antigen complex and initiate an immune response. MHC class I and MHC class II are two main types of MHC molecules, each associated with a distinct antigen processing pathway.
MHC Class I: Presenting Endogenous...
MHC Class I: Presenting Endogenous...
2.0K
Antigens Involved in Adaptive Immunity
1.2K
An antigen is any substance the immune system identifies as foreign and potentially harmful to the body, prompting an immune response. Antigens have two functional properties: immunogenicity and reactivity. Immunogenicity is the ability of an antigen to stimulate a specific immune response. At the same time, reactivity describes the antigen's ability to react with the cells and antibodies produced in response to it.
Complete Antigens
Complete antigens possess both immunogenicity and...
Complete Antigens
Complete antigens possess both immunogenicity and...
1.2K
Ligand Binding and Linkage
5.4K
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...
5.4K
Ligand Binding Sites
14.8K
Proteins are dynamic macromolecules that carry out a wide variety of essential processes; however, the activities of most proteins depend on their interactions with other molecules or ions, known as ligands.
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
14.8K
Cooperative Allosteric Transitions
8.6K
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
8.6K
B Cell Activation and Differentiation
15.8K
The adaptive immune response, a sophisticated defense mechanism, relies on the activation and differentiation of B lymphocytes, or B cells. These processes enable our bodies to mount a tailored response against specific pathogens such as bacteria, free virus particles, toxins, and parasites.
When naive B cells encounter a specific antigen that can bind to the B cell receptor (BCR) on their surface, they undergo sensitization to respond to the antigen's presence. Sensitization begins with...
When naive B cells encounter a specific antigen that can bind to the B cell receptor (BCR) on their surface, they undergo sensitization to respond to the antigen's presence. Sensitization begins with...
15.8K


