In this study, we present the synthesis and incorporation of a metabolic isoleucine precursor compound for selective methylene labeling. The utility of this novel α-ketoacid isotopologue is shown by incorporation into the protein Brd4-BD1, which regulates gene expression by binding to acetylated histones. High quality single quantum ¹³C−¹ H-HSQC were obtained, as well as triple quantum HTQC spectra, which are superior in terms of significantly increased ¹³C-T₂ times. Additionally, large chemical shift perturbations upon ligand binding were observed. Our study thus proves the great sensitivity of this precursor as a reporter for side-chain dynamic studies and for investigations of CH-π interactions in protein-ligand complexes.

在这项研究中，我们提出了用于选择性亚甲基标记的代谢异亮氨酸前体化合物的合成和掺入。这种新型 α-酮酸同位素体的效用通过掺入蛋白 Brd4-BD1 来体现，该蛋白通过与乙酰化组蛋白结合来调节基因表达。获得了高质量的单量子¹³ C− ¹  H-HSQC 以及三量子 HTQC 谱图，其在¹³ C-T ₂倍显着提高方面具有优越性。此外，还观察到配体结合时发生大的化学位移扰动。因此，我们的研究证明了该前体作为侧链动态研究和蛋白质-配体复合物中 CH-π 相互作用的研究报告分子的高度敏感性。