S-S Bond in Proteins

Disulfide bond also known as S-S bond, or sometimes disulfide bridge. It is a covalent bond derived from two thiol groups. More importantly, these bonds observed to play an important role in protein stability and aggregation of large biomolecules.

SS bonds are formed by a thiol/disulfide exchange reaction, and three important factors are required in the reactive groups to form this bond: accessibility, proximity, and reactivity (electrostatic environment).

 

The most common way of creating this bond is by the oxidation of sulfhydryl groups. (2 RSH → RS-SR + 2 H+ + 2 e-) This process of oxidation can produce stable protein dimers, polymers, or complexes, in which the sulfide bonds can help in protein folding.

 

Disulfide bonds can occur two ways:

·         Intramolecularly – occurs within a polypeptide chain and are usually responsible for stabilizing tertiary structures of proteins.

·         Intermolecularly- occurs between polypeptide chains and are attributed to stabilizing quaternary protein structures.

 

 

 

 

 

Following Image credit goes to Wikipedia and Maria Monica Castellanos and Coray M. Colina of Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States

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