In molecular biology, the cohesin domain is a protein domain.

It interacts with a complementary domain, termed the dockerin domain.

The cohesin-dockerin interaction is the crucial interaction for complex formation in the cellulosome.

[1] The scaffolding component of the cellulolytic bacterium Clostridium thermocellum is a non-hydrolytic protein which organises the hydrolytic enzymes into a large complex, called the cellulosome.

Scaffoldin comprises a series of functional domains, amongst which is a single cellulose-binding domain and nine cohesin domains which are responsible for integrating the individual enzymatic subunits into the complex.