Cystine knot
| Cystine-knot domain | |||||||||
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Structure of human chorionic gonadotropin.[1]
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| Identifiers | |||||||||
| Symbol | Cys_knot | ||||||||
| Pfam | PF00007 | ||||||||
| Pfam clan | CL0079 | ||||||||
| InterPro | IPR006208 | ||||||||
| SCOP | 1hcn | ||||||||
| SUPERFAMILY | 1hcn | ||||||||
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A cystine knot is a protein structural motif containing three disulfide bridges (formed from pairs of cysteine residues). The sections of polypeptide that occur between two of them form a loop through which a third disulfide bond passes, forming a rotaxane substructure. It occurs in many proteins across many species and provides considerable structural stability.[2] There are three types of cystine knot, which differ in the topology of the disulfide bonds:[3]
- The Growth Factor Cystine Knot (GFCK)
- Inhibitor Cystine Knot (ICK) common in spider and snail toxins
- Cyclic Cystine Knot, or cyclotide
The growth factor cystine knot (GFCK) was first observed in the structure of Nerve Growth Factor, solved by X-ray crystallography and published in 1991 by Tom Blundell in Nature.[4] All GFCK structures that have been determined are dimeric, but their dimerization modes in different classes are different.[5]
References
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ http://www.cyclotide.com/knots.html
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ PDB: 1bet; Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
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