School of Chemistry, University of Hyderabad, India.
Centre for Cellular and Molecular Biology, Hyderabad, India.
FEBS Lett. 2020 Feb;594(3):509-518. doi: 10.1002/1873-3468.13617. Epub 2019 Oct 9.
The fibronectin type II (FnII) domain, present in diverse vertebrate proteins, plays crucial roles in several fundamental biological processes. PDC-109, the major bovine seminal plasma protein, contains two FnII domains that bind to choline phospholipids on sperm plasma membrane and induce lipid efflux crucial for successful fertilization. PDC-109 also exhibits chaperone-like activity and protects other proteins against various types of stress. Here, we show that a core tryptophan residue is highly conserved across species in the FnII domains. Mutation of conserved tryptophan residues W47, W93, and W106 in the FnII domains of PDC-109 to alanine leads to drastic decrease or complete abolition of membrane-binding and chaperone-like activities. These observations suggest that conserved tryptophans are important for the function of FnII proteins.
纤维连接蛋白 II （FnII）结构域存在于多种脊椎动物蛋白中，在几个基本的生物学过程中发挥着关键作用。PDC-109 是主要的牛精液浆蛋白，含有两个 FnII 结构域，可与精子质膜上的胆碱磷脂结合，并诱导脂质外排，这对成功受精至关重要。PDC-109 还具有分子伴侣样活性，可保护其他蛋白质免受各种类型的应激。在这里，我们表明 FnII 结构域中核心色氨酸残基在物种间高度保守。PDC-109 的 FnII 结构域中保守色氨酸残基 W47、W93 和 W106 突变为丙氨酸会导致膜结合和分子伴侣样活性急剧下降或完全丧失。这些观察结果表明，保守的色氨酸对于 FnII 蛋白的功能很重要。
