Collagen-like polypeptide

Kamitakahara, M., Ohtsuki, C., Morihara, Y., Ogata, S. and Tanihara, M. (2005) Hydroxyapatite deposition on collagen-like polypeptide modified with silanol groups, in Archives of BioCeramics Research (eds F. Watari, T. Akazawa, M. Uo, T. Akasaka), Vol.5, pp. 210-213. 

Berisio, R., Vitagliano, L., Mazzarella, L., and Zagari, A. (2001). Crystal structure of a collagen-like polypeptide with repeating sequence Pro-Hyp-Gly at 1.4A resolution Implications for collagen hydration. Biopolymers 56, 8-13. 

It would seem reasonable to expect that the displacements of the chemical shifts could be used as an intrinsic probe of local environment of a given amino acid residue, if the transferability of the conformation-dependent shifts of polypeptides to more complicated protein systems is guaranteed. Fibrous proteins such as silk fibroin, collagen and collagen-like polypeptides can serve as ideal systems to justify this view, because several crystalline polymorphs are available depending on a variety of physical treatments and the spectral pattern is very simple as compared with those of globular proteins because of the limited numbers of amino acid residues involved. 

Figure 14.2 Models of a collagen-like peptide with a mutation Gly to Ala in the middle of the peptide (orange). Each polypeptide chain is folded into a polyproline type II helix and three chains form a superhelix similar to part of the collagen molecule. The alanine side chain is accommodated inside the superhelix causing a slight change in the twist of the individual chains, (a) Space-filling model, (b) Ribbon diagram. Compare with Figure 14.1c for the change caused by the alanine substitution. (Adapted from J. Bella et al.. Science 266 75-81, 1994.)...

The detection of the collagen-like threefold symmetric polypeptides, polyglycine4 and polyproline5, was the first help to elucidate the collagen structure using a synthetic peptide model. 

Reversible gelation is often encountered in bio-polymeric systems. Typical examples are solutions of polypeptide residues derived from animal collagen [82-84]. In these systems, ordered collagen-like triple helices form the physical crosslinks. 

Collagen is the most abundant extracellular matrix protein family in vertebrates. Proteins in the collagen superfamily all have three polypeptide chains with the required -Gly-Xaa-Yaa- repeated sequence, where Xaa and Yaa are frequently proline and 4-hydroxyproline, respectively. At present, more than 30 molecular species of vertebrate proteins called collagen are classified into 28 types as type I, II, III,..., XXVIII. They are typically called type N collagen , or collagen N . In addition, there are many more collagen-like proteins that... 

The collagen superfamily of proteins includes more than twenty colla gen types, as well as additional proteins that have collagen-like domains. The three polypeptide a-chains are held together by hydro gen bonds between the chains. Variations in the amino acid sequence of the a-chains result in structural components that are about the same size (approximately 1000 amino acids long), but with slightly dif ferent properties. These a-chains are combined to form the various types of collagen found in the tissues. For example, the most common collagen, type I, contains two chains called a1 and one chain called... 

Collagen-like triple helices also occur within other proteins. One of these is protein Clq, a component of the complement system of blood (Chapter 31). This protein interacts with antibodies to trigger a major aspect of the immune response. Clq has six subunits, each made up of three different polypeptide chains of about 200 residues apiece. Beginning a few residues from the N termini, there are over 80 residues in each chain with collagen-like sequences. The three chains apparently form a triple helix within each subunit. However, the C-terminal portions are globular in nature.200 Collagen-like tails also are present on some forms of the enzyme acetylcholinesterase (see Chapter 12C,10). Tire extensins of plant cell walls contain 4-hydroxyproline and evidently have a structure... 

The liquid phase synthesis on PEG has also been used for the conformational analysis of collagen-like sequences by CD studies 237). The attachment to PEG has also permitted the CD spectral delineation of the specific interactions between the polypeptide chains and sidechain groups 238,239). Thus, Anzinger et al. observed that onset of local ordered structures in the mesogenic side chains of polylysine blocks attached to PEG leads to significant, specific alteration in the backbone conformations of the peptide chain 239). 

Collagen is the major insoluble fibrous protein in the extracellular matrix and in connective tissue 80-90% of the collagen in the body consists of types 1, It and 111 (Table 12.2). The collagen superfamily consists of at least 20 collagen types, with as many as 38 distinct polypeptide chains and more than 15 additional proteins that have collagen-like domains. 

Fig. 24.11. C NMR spectra of collagen from (A) bovine achilles tendon and (B-D) of model polypeptides taking collagen-like triple helical structure. (B) (Pro-Ala-Gly) (C) (Pro-Pro-Gly), (D) (Hyp) [61],...

In this chapter we give an overview of the large number of naturally or chemically substituted proline derivatives, their conformational analysis and role in native polypeptides, with an emphasis on their impact on collagen-like structures as well as mimetics for the induction of various turn conformations. 

Turning to natural polypeptides and proteins, we may cite our computations on gramicidin S, collagen-like poly (tripeptides), a-lactalbumin, melittin, and bovine pancreatic trypsin inhibitor (BPTI) as examples. In the case of gramicidin S, a cyclic decapeptide, the computed structure [27, 28] was found to agree [29, 30] with a subsequently-determined X-ray structure [31] (see Fig. 2). Likewise, the computed triple-stranded helical structure of poly(Gly-Pro-Pro) [32] (Fig. 3) has cartesian coordinates that agree with those from a single-crystal X-ray diffraction study of (Pro-Pro-Gly)io [33] within 0.3 A. 

T.R. Anderson, M.E. Marquart, and A.V. Janorkar, Effective release of a broad spectrum antibiotic from elastin-like polypeptide-collagen composite, J. Biomed. Mater. Res. Part A, doi 10.1002/jbm.a.35219, 2014. 

Amruthwar, S. S., Janorkar, A. V. (2013). In vitro evaluation of elastin-like polypeptide-collagen composite scaffold for bone tissue engineering. Dental Materials, 29, 211-220. 

---