The structural basis for peptide selection by the transport receptor OppA
The structural basis for peptide selection by the transport receptor OppA
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DOI：
10.1038/emboj.2009.65
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发表时间：
2009-05-06
期刊：
影响因子：
11.4
通讯作者：
Slotboom, Dirk-Jan
中科院分区：
文献类型：
--
作者：
Berntsson, Ronnie P-A;Doeven, Mark K.;Slotboom, Dirk-Jan
乳球菌寡肽结合蛋白A （OppA）结合的肽长度范围非常宽（4-35个残基），没有明显的序列偏好。在这里，我们给出了OppA在开放和封闭配体构象中的晶体结构。这种结构直接解释了这种蛋白质惊人的混杂性。一个巨大的空腔允许结合非常长的肽，并且对配体的N和C端位置没有限制，这与不同长度的肽的结合是兼容的。出乎意料的是，肽的氨基酸组成（但不是确切的序列）似乎在选择中起作用，偏爱含有至少一种异亮氨酸的富含脯氨酸的肽。这些特性可能与生物体的生理有关：乳杆菌对支链氨基酸具有营养缺陷，并倾向于将富含脯氨酸的酪蛋白作为氨基酸的来源。我们提出了一种基于氨基酸组成而非序列的肽选择新机制。生物医学工程学报，2009,28,1332-1340。doi: 10.1038 / emboj.2009.65;2009年3月19日在线发布
Oligopeptide-binding protein A (OppA) from Lactococcus lactis binds peptides of an exceptionally wide range of lengths (4-35 residues), with no apparent sequence preference. Here, we present the crystal structures of OppA in the open-and closed-liganded conformations. The structures directly explain the protein's phenomenal promiscuity. A huge cavity allows binding of very long peptides, and a lack of constraints for the position of the N and C termini of the ligand is compatible with binding of peptides with varying lengths. Unexpectedly, the peptide's amino-acid composition (but not the exact sequence) appears to have a function in selection, with a preference for proline-rich peptides containing at least one isoleucine. These properties can be related to the physiology of the organism: L. lactis is auxotrophic for branched chain amino acids and favours proline-rich caseins as a source of amino acids. We propose a new mechanism for peptide selection based on amino-acid composition rather than sequence. The EMBO Journal (2009) 28, 1332-1340. doi: 10.1038/emboj.2009.65; Published online 19 March 2009