Check out PMC Labs and inform us what you assume. Study Extra.
Summary
Kadler 1995; Ricard-Blum et al. 2000, 2005; Myllyharju and Kivirikko 2004; Ricard-Blum and Ruggiero 2005; Kadler et al. 2007; Gordon and Hahn 2010) and even when the query “What is collagen, what is not?” For the reason that discovery of collagen II by Miller and Matukas (1969), 26 new collagen sorts have been discovered, and their discovery has been accelerated by molecular biology and gene cloning. A number of opinions on the collagen household have been printed (Miller and Homosexual 1982; van der Relaxation and Garrone 1991;
THE COLLAGEN SUPERFAMILY
A few of them, containing a recognition area contiguous with a collagen-like triple-helical area, are referred to as soluble protection collagens (Fraser and Tenner 2008), and gliomedin is acknowledged as a membrane collagen (Maertens et al. 2007). The factors to call a protein collagen aren’t nicely outlined and different proteins containing one triple-helical area (Desk (Table2)2) aren’t numbered with a Roman numeral to this point and don’t belong to the collagen household sensu stricto.
THE STRUCTURAL ORGANIZATION OF COLLAGENS
SUPRAMOLECULAR ASSEMBLIES OF COLLAGENS
When visualized by electron microscopy after rotary shadowing, collagen molecules are visualized as rods various in size from roughly 75 nm for collagen XII to 425 nm for collagen VII (Ricard-Blum et al. 2000). The molecular construction of collagen XV extracted from tissue has an uncommon form, most molecules being present in a knot/figure-of-eight/pretzel configuration (Myers et al. 2007), though recombinant collagen XV seems elongated in rotary shadowing (Hurskainen et al. 2010). Non-collagenous domains can be characterised by electron microscopy after rotary shadowing (e.g., the trimeric carboxy-terminal NC1 area of collagen XVIII, Sasaki et al.
COLLAGEN BIOSYNTHESIS
The N-propeptide is cleaved by procollagen N-proteinases belonging to the A Disintegrin And Metalloproteinase with Thrombospondin motifs (ADAMTS) household, besides the N-propeptide of the proα1(V) chain that’s cleaved by the procollagen C-proteinase additionally termed Bone Morphogenetic Protein-1 (BMP-1) (Hopkins et al. 2007). BMP-1 cleaves the carboxy-terminal propeptide of procollagens, besides the carboxy-terminal propeptide of the proα1(V) chain, that’s processed by furin. This course of is initiated by the oxidative deamination of lysyl and hydroxylsyl residues catalyzed by the enzymes of the lysyl oxidase household (Mäki 2009).
COVALENT CROSS-LINKING OF COLLAGENS
Glucosepane, probably the most plentiful cross-link in senescent pores and skin collagen, is ready to cross-link one in 5 collagen molecules within the pores and skin of the aged (Sjöberg and Bulterijs 2009). Two lysine-arginine cross-links, pentosidine (a fluorescent product fashioned from ribose), and glucosepane (a nonfluorescent product fashioned from glucose) have been recognized in collagens. Glycation will increase with age and several other superior glycation endproducts act as cross-links that contribute to the progressive insolubilization and to the elevated stiffness of collagens in aged tissues.