立体电子效应影响甘识别
Caitlin M McMahon1, Christine R Isabella1, Ian W Windsor1
1Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States.
Journal of the American Chemical Society
|January 14, 2020
概括
人类智能蛋白-1 (hItln-1) 通过共享的二醇基因与微生物糖结合,立体电子效应影响识别特异性. 这种莱克避免了常见的1,2-二醇甘氨酸,这表明它对不同的细菌物种具有进化特异性.
科学领域:
- 结构生物学
- 碳水化合物化学
- 免疫学
背景情况:
- 莱克是识别和结合特定甘氨酸的蛋白质,在生物过程中起着至关重要的作用.
- 人类智质素-1 (hItln-1) 是一种可溶性学质素,对微生物糖具有异常广泛的特异性,包括具有外循环附近二醇的糖.
- 确切的结构基础和特异性决定因素对hItln-1糖的识别仍然不清楚.
研究的目的:
- 阐明人类智能素-1 (hItln-1) 识别微生物糖的结构机制.
- 研究特定的甘氨酸构成和立体电子效应在HIT1结合中的作用.
- 了解hItln-1如何在结合具有共同结构特征的甘氨酸的情况下实现特异性.
主要方法:
- 使用X射线结晶学来确定hItln-1·KO复合物的高分辨率结构.
- 在蛋白质数据库中对糖构成进行了生物信息分析.
- 使用自然键轨道 (NBO) 计算来评估甘氨酸构造中的稳定力.
主要成果:
- 晶体结构显示了d-glycero-d-talo-oct-2-ulosonic acid (KO) 与hItln-1的结合结构.
- KO和3-deoxy-d-manno-oct-2-ulosonic acid (KDO) 采用一种共同的形状,有利于hItln-1结合,而不是heptoses.
- 除了立体因素外,立体电子效应还能稳定这些偏好的形状,从而影响HITLN-1的特异性.
结论:
- 人类智能蛋白-1 (hItln-1) 的特异性是由立体电子效应决定的,该效应稳定了首选的甘氨酸构造.
- hItln-1 避免与终端1,2-二醇,如N-乙-神经胺酸和l-glycero-α-d-manno-heptose结合.
- 这种选择性结合表明hItln-1已经进化到专门针对不同的细菌物种.
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