Computational Spectroscopy Studies of Model Ternary Complexes of Copper(II), C-Peptide, and Serum Albumin Using...

Area of Science:

• Biochemistry
• Computational Chemistry
• Spectroscopy

Background:

• C-peptide is a biomarker for insulin production and pancreatic diseases.
• C-peptide interacts with metal ions like Cu(II) and proteins such as serum albumin.
• Experimental studies observed a ternary Cu(II)/C-peptide/BSA complex with wavelength-dependent absorption spectra.

Purpose of the Study:

• To gain structural insights into the ternary Cu(II)/C-peptide/BSA complex.
• To computationally model the complex and understand its spectral properties.
• To develop a method for predicting structures with specific absorption characteristics.

Main Methods:

• Time-dependent density functional theory (TD-DFT) was used to compute UV-vis absorption spectra.
• A novel energy penalty geometry optimization method was developed and applied.
• Calculated spectra were compared with experimental data for validation.

Main Results:

• A structural model of the ternary complex was found with absorption frequencies closely matching experimental values (<0.05 eV).
• The computational method accurately reproduced experimental spectra for binary complexes.
• Analysis revealed that the Cu(II)-ligand distance strongly influences the absorption wavelength.

Conclusions:

• The study provides structural insights into the ternary Cu(II)/C-peptide/BSA complex.
• The developed computational approach is effective for predicting complex structures and spectral properties.
• Understanding these interactions is crucial for biomarker and therapeutic applications.