Treviño Matthew A, Amankwah Kofi A, Fernandez Daniel, Weston Scott A, Stewart Claire J, Gallardo Jaime Morales, Shahgholi Mona, Sharaf Naima G
Department of Biology, Stanford University, Stanford, California, USA.
Macromolecular Structure Knowledge Center (MSKC) at Sarafan ChEM-H, Stanford University, Stanford, California, USA; Sarafan ChEM-H Institute, Stanford University, Stanford, California, USA.
J Biol Chem. 2024 Nov;300(11):107853. doi: 10.1016/j.jbc.2024.107853. Epub 2024 Oct 1.
YcjN is a putative substrate binding protein expressed from a cluster of genes involved in carbohydrate import and metabolism in Escherichia coli. Here, we determine the crystal structure of YcjN to a resolution of 1.95 Å, revealing that its three-dimensional structure is similar to substrate binding proteins in subcluster D-I, which includes the well-characterized maltose binding protein. Furthermore, we found that recombinant overexpression of YcjN results in the formation of a lipidated form of YcjN that is posttranslationally diacylated at cysteine 21. Comparisons of size-exclusion chromatography profiles and dynamic light scattering measurements of lipidated and nonlipidated YcjN proteins suggest that lipidated YcjN aggregates in solution via its lipid moiety. Additionally, bioinformatic analysis indicates that YcjN-like proteins may exist in both Bacteria and Archaea, potentially in both lipidated and nonlipidated forms. Together, our results provide a better understanding of the aggregation properties of recombinantly expressed bacterial lipoproteins in solution and establish a foundation for future studies that aim to elucidate the role of these proteins in bacterial physiology.
YcjN是一种假定的底物结合蛋白，由大肠杆菌中参与碳水化合物导入和代谢的一组基因表达。在此，我们确定了YcjN的晶体结构，分辨率为1.95 Å，揭示其三维结构与D-I亚簇中的底物结合蛋白相似，该亚簇包括特征明确的麦芽糖结合蛋白。此外，我们发现YcjN的重组过表达导致形成一种脂化形式的YcjN，其在半胱氨酸21处进行翻译后双酰化。对脂化和非脂化YcjN蛋白的尺寸排阻色谱图谱和动态光散射测量结果的比较表明，脂化的YcjN通过其脂质部分在溶液中聚集。此外，生物信息学分析表明，类似YcjN的蛋白可能存在于细菌和古细菌中，可能以脂化和非脂化两种形式存在。总之，我们的结果有助于更好地理解重组表达的细菌脂蛋白在溶液中的聚集特性，并为未来旨在阐明这些蛋白在细菌生理学中的作用的研究奠定基础。
