In molecular biology, the cohesin domain is a protein domain

Protein domain

A protein domain is a part of protein sequence and structure that can evolve, function, and exist independently of the rest of the protein chain. Each domain forms a compact three-dimensional structure and often can be independently stable and folded. Many proteins consist of several structural...

. It interacts

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with a complementary domain, termed the dockerin domain

Dockerin

Dockerin is a protein domain found in the Cellulosome cellular structure. It is part of endoglucanase enzymes. The dockerin's binding partner is the cohesin domain. This interaction is essential to the construction of the Cellulosome complex . The Dockerin domain has two in-tandem repeats of a...

. The cohesin-dockerin interaction is the crucial interaction for complex

Protein complex

A multiprotein complex is a group of two or more associated polypeptide chains. If the different polypeptide chains contain different protein domain, the resulting multiprotein complex can have multiple catalytic functions...

 formation in the cellulosome.

The scaffoldin component of the cellulolytic bacterium Clostridium thermocellum is a non-hydrolytic protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 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

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 subunits

Protein subunit

In structural biology, a protein subunit or subunit protein is a single protein molecule that assembles with other protein molecules to form a protein complex: a multimeric or oligomeric protein. Many naturally occurring proteins and enzymes are multimeric...

into the complex.