Interplay between hydrogen and chalcogen bonds in cysteine

Area of Science:

• Biochemistry
• Structural Biology
• Chemical Biology

Background:

• Protein structures rely on chemical interactions between amino acids.
• Cysteine's thiol group can form both hydrogen bonds and chalcogen bonds.
• These interactions can compete, influencing protein stability.

Purpose of the Study:

• To investigate the competition between hydrogen bonds and chalcogen bonds involving cysteine.
• To analyze the prevalence and interplay of these bonds in protein structures.

Main Methods:

• Survey of the Protein Data Bank (PDB) for bond interactions involving cysteine.
• Analysis of bonding patterns and frequencies.

Main Results:

• Hydrogen bonds are significantly more common (40-50 times) than chalcogen bonds involving cysteine.
• Despite lower frequency, chalcogen bonds are observed, sometimes concurrently with hydrogen bonds.
• Cysteine thiol groups forming chalcogen bonds often act as hydrogen bond donors.

Conclusions:

• Hydrogen bonds are generally more prevalent than chalcogen bonds, suggesting they are often stronger.
• Cysteine can participate in multiple bonding interactions simultaneously.
• Understanding these competing interactions is crucial for predicting and stabilizing protein structures.