Beta-sandwich, β-sandwich domains consisting of 80 to 350 amino acids occur commonly in
proteins
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, respo ...
. They are characterized by two opposing antiparallel
beta sheet
The beta sheet, (β-sheet) (also β-pleated sheet) is a common motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a ge ...
s (β-sheets).
The number of strands found in such domains may differ from one protein to another. β-sandwich domains are subdivided in a variety of different folds. The
immunoglobulin-type fold found in
antibodies
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of ...
(Ig-fold) consists of a sandwich arrangement of 7 and 9 antiparallel
β-strands arranged in two
β-sheets
The beta sheet, (β-sheet) (also β-pleated sheet) is a common motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a gen ...
with a
Greek-key topology.
The Greek-key topology is also found in
Human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
Transthyretin
Transthyretin (TTR or TBPA) is a transport protein in the plasma and cerebrospinal fluid that transports the thyroid hormone thyroxine (T4) and retinol to the liver. This is how transthyretin gained its name: ''transports thyroxine and retinol' ...
. The
jelly-roll topology is found in carbohydrate binding proteins such as
concanavalin A
Concanavalin A (ConA) is a lectin (carbohydrate-binding protein) originally extracted from the jack-bean (''Canavalia ensiformis''). It is a member of the legume lectin family. It binds specifically to certain structures found in various sugars ...
and various
lectins
Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in rec ...
, in the
collagen
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whol ...
binding domain of ''
Staphylococcus aureus
''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posit ...
''
Adhesin and in modules that bind
fibronectin
Fibronectin is a high- molecular weight (~500-~600 kDa) glycoprotein of the extracellular matrix that binds to membrane-spanning receptor proteins called integrins. Fibronectin also binds to other extracellular matrix proteins such as collage ...
as found in
Tenascin
Tenascins are extracellular matrix glycoproteins. They are abundant in the extracellular matrix of developing vertebrate embryos and they reappear around healing wounds and in the stroma of some tumors.
Types
There are four members of the tenas ...
(Third Fibronectin Type III Repeat). The
L-type lectin domain
In molecular biology the L-like lectin domain is a protein domain found in lectins which are similar to the leguminous plant lectins.
Lectins are structurally diverse proteins that bind to specific carbohydrates. This family includes the VIP36 ...
is a variation of the jelly roll fold. The
C2 domain
A C2 domain is a protein structural domain involved in targeting proteins to cell membranes. The typical version (PKC-C2) has a beta-sandwich composed of 8 beta sheet, β-strands that co-ordinates two or three calcium ions, which bind in a cavity ...
in its typical version (PKC-C2) is a β-sandwich composed of 8
beta-strand
The beta sheet, (β-sheet) (also β-pleated sheet) is a common structural motif, motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone chain, backb ...
s (β-strands).
References
{{Protein-stub
Protein structural motifs