Classification of Protein Disulphide Bonds

Area of Science:

• Biochemistry
• Structural Biology
• Computational Biology

Background:

• Protein disulphide bonds link cysteine residues, stabilizing polypeptide chains.
• Disulphide bond conformations are defined by five dihedral angles, yielding 20 possibilities.
• All 20 known disulphide conformations are observed in existing protein structures.

Purpose of the Study:

• To classify disulphide bond conformations in proteins.
• To identify disulphide conformations with significant internal strain.
• To investigate the relationship between strained disulphide bonds and protein allosteric function.

Main Methods:

• Utilized force distribution analysis to examine pairwise forces between cysteine residues.
• Classified 20 distinct disulphide conformations based on dihedral angles.
• Analyzed the association of specific disulphide conformations with allosteric proteins.

Main Results:

• Identified two disulphide conformations, -RHstaple and -/+RHhook, as possessing significant strain.
• These two strained conformations are prevalent in proteins exhibiting allosteric regulation.
• Developed an online tool for comprehensive disulphide bond analysis in protein structures.

Conclusions:

• The -RHstaple and -/+RHhook disulphide bonds represent strained conformations.
• These strained conformations are functionally relevant, particularly in allosteric proteins.
• An accessible online tool aids in analyzing disulphide bond characteristics and their structural implications.