Collagen containing

It is well known that native collagen containes tripeptide sequences, which alone are not capable of building up a triple helix (e.g. Gly-Pro-Leu, Gly-Pro-Ser) when they exist as homopolypeptides. The synthesis of threefold covalently bridged peptide chains opens up the possibility of investigating the folding properties of such weak helix formers, because the bridging reduces the entropy loss during triple-helix formation and thereby increases the thermodynamic stability of the tertiary structure. Therefore, we have... 

It is known that native collagen contains tripeptide sequences which, because of being homopolypeptides, are not able to give rise to triple-helical tertiary structures (e.g. Gly-Pro-Leu, Gly-Pro-Ser). The reason for this and for the above-mentioned low thermostability of the synthetic homopolypeptides is presumably to be found in the fact that in the case of the model peptides with their monotonously repeated tripeptide sequences, special interactions between the side chains of the different amino acid residues as postulated by Ward and Mason are no more possible157). 

Collagen is the most abundant protein in the animal kingdom approximately 19 types have been isolated. All collagens contain greater or lesser stretches of triple helix and the repeating stmcture (Gly-X-Y). ... 

The second class of AChEs exists as heteromeric assemblies of catalytic and structural subunits. One form consists of up to 12 catalytic subunits linked by disulfide bonds to filamentous, collagen-containing structural subunits. These forms are often termed asymmetric, since the tail unit imparts substantial dimensional asymmetry to the molecule. The collagenous tail unit links by disulfide bonding at its proline rich N-terminus through a coiled coil arrangement to the C-terminus of two of the catalytic subunits [30]. The tail unit associates with the basal lamina of the synapse rather than the plasma membrane. 

COLl domain of type XXIII collagen contains multiple copies of a conserved KGD motif used for integrin-mediated cell adhesion by collagen type XVII. ... 

Type XXIII collagen contains about 540 residues. The NCI domain contains a transmembrane sequence and is followed by COLl, NC2, COL2, NC3, COL3, and NC4 at the C-terminus. Furin proteinases may cleave the NCI domain, and the cleaved secreted portion of type XXIII collagen may also form multimers and display low-affinity binding to heparin in vitro ... 

Extensive analysis of cyanogen bromide fragmented peptides of type I, III, and V collagens by MALDI-MS has shown that type V collagen from bovine skin is highly glycosylated, while type I and III collagens contain... 

Two common examples are the a-helix and the P-pleated sheet. These shapes are reinforced by hydrogen bonds. An individual protein may contain both types of secondary structures. Some proteins, like collagen, contain neither but have their own more characteristic secondary structures. 

Hydroxyproline and hydroxylysine Collagen contains hydroxy proline (hyp) and hydroxylysine (hyl), which are not present in most other proteins. These residues result from the hydroxylation of some of the proline and lysine residues after their incorporation into polypeptide chains (Figure 4.6). The hydroxylation is, thus, an example of posttranslational modification (see p. 440). Hydroxy proline is important in stabilizing the triple-helical structure of colla gen because it maximizes interchain hydrogen bond formation. 

Removal of introns Maturation of eukaryotic mRNA usually involves the removal of RNA sequences, which do not code for protein (introns, or intervening sequences) from the primary tran script. The remaining coding sequences, the exons, are spliced together to form the mature mRNA. The molecular machine that accomplishes these tasks is known as the spliceosome. [Note A few eukaryotic primary transcripts contain no introns. Others con tain a few introns, whereas some, such as the primary transcripts for the a-chains of collagen, contain more than fifty intervening sequences that must be removed before mature mRNA is ready for translation.]... 

Privalov and Mrevlishvili14,188,189) made calorimetric studies on collagen. Up to 0.3 g water/g collagen is strongly bonded, this water shows no crystallisation until at liquid He T. No phase transition in collagen containing 2-3 mole water/100 g... 

Fig. 2. (A) The molecular structure of collagen contains three left-handed helical et-...

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