Dockerin is a
protein domain
In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist o ...
found in the
cellulosome cellular structure of
anaerobic bacteria
An anaerobic organism or anaerobe is any organism that does not require molecular oxygen for growth. It may react negatively or even die if free oxygen is present. In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenat ...
. It is found on many
endoglucanase enzymes. The dockerin's binding partner is the
cohesin
Cohesin is a protein complex that mediates sister chromatid cohesion, homologous recombination, and DNA looping. Cohesin is formed of SMC3, SMC1, SCC1 and SCC3 ( SA1 or SA2 in humans). Cohesin holds sister chromatids together after DNA re ...
domain, located on the
scaffoldin protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...
. This interaction between the dockerin domains of the
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
constituents of the cellulosome and the cohesin domains of the scaffoldin protein is essential to the construction of the cellulosome complex.
The Dockerin domain has two in-tandem repeats of a non-
EF hand
The EF hand is a helix–loop–helix structural domain or ''motif'' found in a large family of calcium-binding proteins.
The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, in ...
calcium binding motif. Each motif is characterized by a
loop-helix structure. The three-dimensional structure of dockerin has been determined in solution,
[; ] as well as in complex with Cohesin.
[; ]
There are three types of Dockerin domains: I, II and III which bind to Cohesin Type I, Cohesin Type II and Cohesin Type III respectively. A type I dockerin domain is 65-70
residues long.
InterPro
InterPro is a database of protein families, protein domains and functional sites in which identifiable features found in known proteins can be applied to new protein sequences in order to functionally characterise them.
The contents of InterPro c ...
: The binding specificity of Type I interaction was well studied by structural and
mutagenesis
Mutagenesis () is a process by which the genetic information of an organism is changed by the production of a mutation. It may occur spontaneously in nature, or as a result of exposure to mutagens. It can also be achieved experimentally using l ...
studies. Type II interaction is less well characterized.
See also
*
EF hand
The EF hand is a helix–loop–helix structural domain or ''motif'' found in a large family of calcium-binding proteins.
The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, in ...
*
cellulosome
References
External links
Protein Structure:
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Specificity Characterization:
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* {{cite journal , vauthors=Jindou S, Soda A, Karita S, Kajino T, Béguin P, Wu JH, Inagaki M, Kimura T, Sakka K, Ohmiya K, title=Cohesin-dockerin interactions within and between Clostridium josui and Clostridium thermocellum: binding selectivity between cognate dockerin and cohesin domains and species specificity, journal=J Biol Chem, volume=279, issue=11, pages=9867–9874, year=2004 , pmid=14688277 , doi=10.1074/jbc.M308673200, doi-access=free
Protein structural motifs
Protein domains