In molecular biology, the type IV collagen C4 domain (or collagen IV NC1 domain) is a duplicated domain present at the C-terminus of type IV collagens. Each type IV collagen contains a long triple-helical collagenous domain flanked by a short 7S domain of 25 amino acids and a globular non-collagenous C4 domain of ~230 amino acids at the N and C terminus, respectively. In protomer assembly, the C4 domains of three chains interact, forming a C4 trimer, to select and register chains for triple helix formation. In network assembly, the C4 trimers of two protomers interact, forming a C4 hexamer structure, to select and connect protomers.[1][2][3]
| C4 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 the 1.9-a crystal structure of the noncollagenous (nc1) domain of human placenta collagen iv shows stabilization via a novel type of covalent met-lys cross-link | |||||||||
| Identifiers | |||||||||
| Symbol | C4 | ||||||||
| Pfam | PF01413 | ||||||||
| Pfam clan | CL0056 | ||||||||
| InterPro | IPR001442 | ||||||||
| SMART | C4 | ||||||||
| PROSITE | PDOC00031 | ||||||||
| MEROPS | C47 | ||||||||
| SCOP2 | 1hra / SCOPe / SUPFAM | ||||||||
| TCDB | 2.A.16 | ||||||||
| |||||||||
The collagen IV C4 domain contains 12 cysteines, and all of them are involved in disulphide bonds. It folds into a tertiary structure with predominantly beta-strands. The collagen IV C4 domain is composed of two similarly folded subdomains stabilised by 3 intrachain disulphide bonds involving the following pairs: C1-C6, C2-C5, and C3-C4. Each subdomain represents a compact disulphide-stabilised triangular structure, from which a finger-like hairpin loop projects into an incompletely formed six-stranded beta-sheet of an adjacent subdomain of the same or of an adjacent chain clamping the subdomains tightly together.[1][2][3]
References
edit- ^ a b Than ME, Henrich S, Huber R, Ries A, Mann K, Kuhn K, Timpl R, Bourenkov GP, Bartunik HD, Bode W (May 2002). "The 1.9-A crystal structure of the noncollagenous (NC1) domain of human placenta collagen IV shows stabilization via a novel type of covalent Met-Lys cross-link". Proc. Natl. Acad. Sci. U.S.A. 99 (10): 6607–12. doi:10.1073/pnas.062183499. PMC 124450. PMID 12011424.
- ^ a b Sundaramoorthy M, Meiyappan M, Todd P, Hudson BG (August 2002). "Crystal structure of NC1 domains. Structural basis for type IV collagen assembly in basement membranes". J. Biol. Chem. 277 (34): 31142–53. doi:10.1074/jbc.M201740200. PMID 11970952.
- ^ a b Vanacore RM, Shanmugasundararaj S, Friedman DB, Bondar O, Hudson BG, Sundaramoorthy M (October 2004). "The alpha1.alpha2 network of collagen IV. Reinforced stabilization of the noncollagenous domain-1 by noncovalent forces and the absence of Met-Lys cross-links". J. Biol. Chem. 279 (43): 44723–30. doi:10.1074/jbc.M406344200. PMID 15299013.