Type I collagen

The amino acid sequence of the collagen type I (bone, skin, tendon) is nearly completely known6. The sequence of the different tripeptides in the archain shows a more or less statistic distribution. The content of the tripeptides in the archain of type I collagen, however, is quite different (Table 1). 

Table 1. Frequency of some tripeptides in the a,-chain of type I collagen...

In the archain of the type I-collagen, the content5 of the different categories of tripeptides is as follows ... 

Fig. 37. Dependence of the thermodynamic parameters AH and AS of triple-helix formation on the imino acid content of the peptides (obtained by cleavage of calf skin-type I collagene with cyanogene and subequent isolation by column chromatrography)3) and of the native neutral salt-soluble skin collagene of various animals. The entropy values are denoted by dotted lines...

Fairgrieve, S.I. 1993 Amino acid residue analysis of Type I collagen in human hard tissue an assessment of cribra orbitalia in an ancient skeletal samplefrom tomb 31, site 31/435-D5-2, Dakhleh Oasis, Egypt. Ph.D. dissertation, University of Toronto. 

Bernstein EF, Lee J, Brown DB, Yu R, Van Scott E (2001) Glycolic acid treatment increases type I collagen mRNA and hyaluronic acid content of human skin. Dermatol Surg 27(5) 429-433... 

Figure 48-11. Schematic illustration of the major cells present in membranous bone. Osteoblasts (lighter color) are synthesizing type I collagen, which forms a matrix that traps cells. As this occurs, osteoblasts gradually differentiate to become osteo-cytes. (Reproduced, with permission, from Junqueira LC, Carneiro J Basic Histology. Text Atlas, 10th ed. McGraw-Hill, 2003.)...

Different tissues in the body have different types of collagen (there are 27 in total) classified as collagen types I, II, and so on. Type I collagen, for example, the most abundant collagen of the human body, makes up the tendons and the organic part of bone type II collagen makes up articular cartilage type IV makes up the eye lens type VII and type XI colla-... 

Morimoto K, Kawabata K, Kunii S, Hamano K, Saito T, Tonomura B (2009) Characterization of type I collagen fibril formation using thioflavin T fluorescent dye. J Biochem 145(5) 677... 

Ellerbroek, S.M. et al. (2001) Functional interplay between type I collagen and cell surface matrix metalloproteinase activity./. Biol. Chem. 276(27), 24833-24842. 

Gaudet, C. et al. (2003) Influence of type I collagen surface density on fibroblast spreading, motility, and contractility. Biophys. J. 85, 3329-3335. 

Type I collagen molecules are heterotrimeric molecules with an a chain composition of two al (I) chains and one o 2(I) chain from the COLlAl and COLl A2 genes, respectively. This a chain composition is written as [a 1(1)] 20 2 (I). A type I collagen molecule is synthesized as a procollagen type I molecule. The N- and C-terminal propeptides are cleaved as part of the processing in tissues and are called N- and C-propeptides, respectively. The human pro-o (I) and pro-o 2(I) have 246 and 247 residues in their C-propeptides, respectively. The C-propeptide contains interchain disulfide bonds, which are important for the stabilization of the three a chains in the endoplasmic reticulum (ER). 

Type I collagen can interact with various other molecules in the extracellular matrix and on the cell surface. Cell receptors of type I collagen have been identified and include the heterodimeric integrin family receptors, ctl, 0 2, olO, and ol 1, especially o2/3l, the receptor tyrosine kinase discoidin domain receptor (DDR), and the heparan sulfate membrane proteoglycan syndecan family... 

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