Although essential to numerous biotech applications, knowledge of molecular recognition by arginine-rich motifs in live cells remains limited. ¹H,¹⁵N HSQC and ¹⁹F NMR spectroscopies were used to investigate the effects of C-terminal −GR_n (n = 1–5) motifs on GB1 interactions in Escherichia coli cells and cell extracts. While the “biologically inert” GB1 yields high-quality in-cell spectra, the −GR_n fusions with n = 4 or 5 were undetectable. This result suggests that a tetra-arginine motif is sufficient to drive interactions between a test protein and macromolecules in the E. coli cytoplasm. The inclusion of a 12 residue flexible linker between GB1 and the −GR₅ motif did not improve detection of the “inert” domain. In contrast, all of the constructs were detectable in cell lysates and extracts, suggesting that the arginine-mediated complexes were weak. Together these data reveal the significance of weak interactions between short arginine-rich motifs and the E. coli cytoplasm and demonstrate the potential of such motifs to modify protein interactions in living cells. These interactions must be considered in the design of (in vivo) nanoscale assemblies that rely on arginine-rich sequences.

中文翻译：

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短精氨酸基序驱动大肠杆菌细胞质中的蛋白质黏附

尽管对于许多生物技术应用来说都是必不可少的，但是通过活细胞中富含精氨酸的基序进行分子识别的知识仍然有限。^使用1 H，¹⁵ N HSQC和¹⁹ F NMR谱图研究C末端-GR _n（n = 1-5）基序对大肠杆菌细胞和细胞提取物中GB1相互作用的影响。尽管“生物惰性” GB1可产生高质量的细胞内光谱，但无法检测到n = 4或5的-GR _n融合体。该结果表明，四精氨酸基序足以驱动大肠杆菌中测试蛋白与大分子之间的相互作用。细胞质。GB1和-GR ₅基序之间包含12个残基的柔性连接子不能改善“惰性”结构域的检测。相反，在细胞裂解液和提取物中可检测到所有构建体，表明精氨酸介导的复合物是弱的。这些数据一起揭示了富含精氨酸的短基序与大肠杆菌细胞质之间弱相互作用的重要性，并证明了此类基序修饰活细胞中蛋白质相互作用的潜力。在依赖于富含精氨酸的序列的（体内）纳米级组件的设计中必须考虑这些相互作用。