Exploring the binding interaction between copper ions and Candida rugosa lipase

Area of Science:

• Biochemistry
• Enzymology
• Toxicology

Background:

• Copper's widespread use raises toxicity concerns.
• Limited understanding of copper ion interactions with digestive enzymes.

Purpose of the Study:

• Investigate copper ion effects on Candida rugosa lipase (CRL) conformation and activity.
• Elucidate the molecular mechanism of copper-lipase binding.

Main Methods:

• Isothermal titration calorimetry (ITC)
• Multiple spectral techniques (e.g., fluorescence, circular dichroism)
• Molecular simulation
• Enzyme activity assays

Main Results:

• Copper ions bind to CRL with a binding affinity constant (K) of (2.91 ± 0.619) × 10^-3 M^-1.
• Binding is spontaneous, driven primarily by hydrophobic forces.
• Copper binding compacts the protein structure, alters secondary structure, and opens the enzyme's 'lid' to enter the active site.
• CRL activity significantly increased in the presence of copper ions.

Conclusions:

• Copper ions induce significant molecular and conformational changes in CRL.
• These structural alterations lead to enhanced lipase activity.
• The findings underscore the need for greater attention to copper toxicity at the molecular level.