Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523-1872 , United States.
Laboratoire de Chimie de Coordination , CNRS , BP 44099, 31077 Toulouse Cedex 4 , France.
Inorg Chem. 2018 May 7;57(9):4791-4794. doi: 10.1021/acs.inorgchem.8b00182. Epub 2018 Apr 12.
The interpeptidic exchange of Cu(II) between biologically relevant peptides like Gly-His-Lys (GHK) was measured through proximity static fluorescence quenching of a noncoordinating tryptophan residue by Cu(II). The inability to spectrally distinguish between starting and final Cu(HGHK) complexes by the current methods was solved by the replacement of noncoordinating lysine for tryptophan in the starting complex, Cu(HGHW). Because the apoGHW is the only fluorescent species, the recovered fluorescence is directly proportional to the [Cu(II)] between GHW and GHK. The apparent second-order rate constants of the exchanges from Cu(HGHW) to GHK and DAHK are 1.6 (±0.2) × 10 and 5.0 (±0.7) × 10 M s, respectively. The easy-to-implement kinetic fluorescent method described here for Cu(II) interpeptidic exchange can be expanded to other biological systems.
通过非配位色氨酸残基与 Cu(II)的临近静态荧光猝灭，测量了生物相关肽（如 Gly-His-Lys (GHK)）之间的 Cu(II)肽间交换。通过将起始配合物 Cu(HGHW)中的非配位赖氨酸替换为色氨酸，解决了当前方法无法通过光谱区分起始和最终 Cu(HGHK)配合物的问题。由于 apoGHW 是唯一具有荧光的物质，因此恢复的荧光与 GHW 和 GHK 之间的 [Cu(II)]成正比。从 Cu(HGHW)到 GHK 和 DAHK 的交换的表观二级速率常数分别为 1.6(±0.2)×10 和 5.0(±0.7)×10 M s。此处描述的用于 Cu(II)肽间交换的易于实施的动力学荧光方法可以扩展到其他生物系统。
