Computational Study Reveals How Copper Binds to GHK Peptide
Background
The Glycyl-L-Histidyl-L-Lysine (GHK) peptide is a naturally occurring human plasma peptide renowned for its diverse biological activities, including wound healing, anti-inflammatory effects, and tissue regeneration. Many of these beneficial properties are attributed to its strong ability to chelate, or bind, copper (Cu(II)) ions, forming the GHK-Cu complex. However, the precise molecular architecture and stability of this copper binding within the GHK peptide have not been fully elucidated through detailed computational modeling.
Results
The computational analyses revealed significant insights into the Cu-GHK complex. Relative energy and geometry of the identified conformations showed good agreement between the GFN2-xTB semi-empirical and B3LYP-D DFT levels, validating the models. The molecular dynamics simulation demonstrated the stability of the copper-peptide binding over the entire 100 ps trajectory. Crucially, four equatorial bonds involving 3 nitrogen atoms and 1 oxygen atom (3N1O coordination) remained consistently stable throughout the simulation, forming the core binding site. A fifth bond in an apical position, originating from the C-terminal carboxylate, was observed to be more fluxional, indicating a less stable or transient interaction. The automated conformer and rotamer search algorithm, CREST, also successfully predicted the correct metal binding position.
Why It Matters
This theoretical study provides a fundamental understanding of the copper-GHK binding mechanism, which is essential for comprehending the peptide's biological functions. The detailed insights into the coordination geometry and bond stability could facilitate the rational design of novel GHK-based therapeutics with optimized copper binding properties, potentially leading to enhanced efficacy in applications like wound healing or anti-aging. Future work should focus on experimental validation of these computational predictions, potentially through spectroscopic methods, to bridge the gap towards clinical development.