Amyloid-like fibril formation

Srisailam S, Kumar TK, Rajalingam D, Kathir KM, Sheu HS, Jan FJ, Chao PC, Yu C (2003) Amyloid-like fibril formation in an all beta-barrel protein. Partially structured intermediate state(s) is a precursor fa-... 

Yutani K, Takayama G, Goda S, Yamagata Y, Maid S, Namba K, Tsunasawa S, C asahara K (2000) The process of amyloid-like fibril formation by methionine aminopeptidase from a hyperthermophile, Pyro-coccus furiosus. Biochemistry 39 2769-2777... 

The extreme stability of amyloid and amyloid-like fibrils is difficult to understand in terms of the three classes of fibril models. For the Refolding models, it has been suggested that the amyloid conformation is a default conformation for a polypeptide chain (Dobson, 1999). However, these models do not give a clear indication of what types of interactions differ in the amyloid conformation versus the native conformation, and so it is unclear why the amyloid conformation should be more stable. Also, it seems that the elevated protein concentrations associated with fibril formation might disproportionately favor nonspecific aggregation of the destabilized intermediate over amyloid fibril formation. 

Klafki, H. W., Pick, A. I., Pardowitz, I., Cole, T., Awni, L. A., Barnikol, H. U., Mayer, F., Kratzin, H. D., and Hilschmann, N. (1993). Reduction of disulfide bonds in an amyloidogenic Bence Jones protein leads to formation of amyloid-like fibrils in vitro. Biol. Chem. Hoppe Seyfer374, 1117-1122. 

The protein elastin presents another opportunity to create amyloid-like fibrils from natural proteins for the purpose of developing biomaterials. Elastin is found in tissue where it imparts elastic recoil, and fibrils formed from this protein may demonstrate some of the elastic properties of the constituent elastic proteins (Bochicchio et al., 2007). Elastin typically contains the sequence poly(ZaaGlyGlyYaaGly) (where Zaa, Yaa = Val or Leu) (Tamburro et al., 2005), and short stretches of the protein retain the ability to form structures similar to the original protein. Simple proline to glycine mutations in the hydrophobic domains of elastin can induce the formation of amyloid-like fibrils (Miao et al., 2003), suggesting that fibrillar materials can be easily generated from these sequences. 

Wang W, Hecht MH (2002) Rationally designed mutations convert de novo amyloid-like fibrils into monomeric beta-sheet proteins. Proc Natl Acad Sci USA 99 2760-2765 Watson AA, FairUe DP, Craik DJ (1998) Solution structure of methionine-oxidized amyloid beta.-peptide (1 0). Does oxidation affect conformational switching Biochemistry 37 12700-12706 Waugh DF (1957) A mechanism for the formation of fibrils from protein molecules. J Cell Physiol 49 145-164... 

Peptides composed of various coded and noncoded amino acid residues self-assemble to form various types of supramolecular architectures, including supramolecular helices and sheets, nanotubes, nanorods, nanovesicles, and nanofibers. The higher-order self-assembly of supramolecular (3-sheets or supramolecular helices composed of short synthetic acyclic peptides leads to the formation of amyloid-like fibrils. Synthetic cyclic peptides were used in supramolecular chemistry as molecular scaffolding for artificial receptors, so as to host various chiral and achiral ions and other small neutral substrates. Cyclic peptides also self-assemble like their acyclic counterparts to form supramolecular structures, including hollow nanotubes. Self-assembling cyclic peptides can be served as artificial ion channels, and some of them exhibit potential antimicrobial activities against drug-resistant bacteria. 

Template-o , which is a designed coiled coil. To encourage a conformational switch, residues at / positions were changed from glutamine to threonine to produce Template-ofT. Below 70 °C, the peptide is cK-helical and above this temperature it forms -structured amyloid-like fibrils. Cross-linking the peptides to achieve a )8-hairpin-like conformation increases amyloid fibril formation. 

Inoue et al. (2003) found that silk proteins will form rodlike structures and that those structure will assemble into comblike or fabric-like superstructure. The scale differences between the rods (nanometers) and the superstructure (micrometers) would suggest that the rod formation is governed by amyloid fibril formation and that the supramolecular arrangement is governed by the properties of the rod (Oroudjev et al., 2002 Putthanarat et al., 2000), namely surface interaction and hydration. Three levels of association could be considered (i) within the proteins internal /1-strands will organize to form intra /1-sheet structures, (ii) /1-sheets from neighboring molecules will associate to form fibril subunits, and (iii) the fibril subunits will further associate to form larger fibrils or rods. 

Lashuel, H. A., Petre, B. M., Wall, J., Simon, M., Nowak, R. J., Walz, T., and Lansbury, P. T., Jr. (2002). Alpha-synuclein, especially the Parkinson s disease-associated mutants, forms pore-like annular and tubular protofibrils./. Mol. Biol. 322,1089-1102. LeVine, H. (1993). Thioflavine T interaction with synthetic Alzheimer s disease beta-amyloid peptides Detection of amyloid aggregation in solution. Protein Sci. 2, 404—410. Lin, H., Bhatia, R., and Lai, R. (2001). Amyloid beta protein forms ion channels Implications for Alzheimer s disease pathophysiology. FASEB J. 15, 2433-2444. Lorenzo, A., and Yankner, B. A. (1994). Beta-amyloid neurotoxicity requires fibril formation and is inhibited by Congo red. Proc. Natl. Acad. Sci. USA 91, 12243-12247. Luhrs, T., Ritter, C., Adrian, M., Riek-Loher, D., Bohrmann, B., Dobeli, H., Schubert, D., and Riek, R. (2005). 3D structure of Alzheimer s amyl o id-( be la) (1—12) fibrils. Proc. Natl. Acad. Sci. USA 102, 17342-17347. 

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