An Infrared Study of Fibril Formation in Insulin from Different Sources
Amyloid fibrils are proteinaceous aggregates that can be formed in the process of degenerative diseases, such as Alzheimer’s and Creutzfeldt-Jakob diseases. The process of fibril formation can also be observed, under appropriate conditions, in many proteins not involved in neurodegenerative diseases. Insulin, a peptide hormone consisting of two polypeptides linked together by two interchain and one intrachain disulfide bonds, is a model of fibril formation that has produced a wealth of biochemical and structural data making it an excellent model for amyloid studies. Insulin from different mammal species, such as human recombinant, bovine and porcine, has small differences in sequence that produce variations in the three-dimensional structure. Infrared spectroscopy, although it is not a high-resolution technique, it presents the advantages of fast-time response and wider applicability required for studying aggregated materials. The time-course of fibril formation can be followed looking at the appearance of a characteristic band in the region of β-sheet structure. Human insulin, with a different aminoacid in the Nterminal segment, has a lower time in fibril formation than bovine or porcine. The wavenumber and the percentage of the band corresponding to the fibril is different in bovine as compared with human and porcine insulin, what is associated with a change in aminoacids 8 and 10 located in the intrachain disulfide bond. The results show that even if the macromolecular structure of the fibrils is alike, the process is different depending on small changes in protein sequence.
Keywords: Amyloid, Fibrils, Infrared spectroscopy, Insulin, Protein structure
KeywordsZinc Surfactant Toxicity Iodine Amide
Anfinsen, C.B. (1973) Principles That Govern Folding of Protein Chains. Science
: 223-230.CrossRefADSGoogle Scholar
Arrondo, J.L.R. and Goñi, F.M. (1999) Structure and dynamics of membrane proteins as studied by infrared spectroscopy. Prog. Biophys. Mol. Biol.
: 367-405.CrossRefGoogle Scholar
Arrondo, J.L.R., Muga, A., Castresana, J., and Goñi, F.M. (1993) Quantitative studies of the structure of proteins in solution by Fourier-transform infrared spectroscopy. Prog. Biophys. Mol. Biol.
: 23-56.CrossRefGoogle Scholar
Bouchard, M., Zurdo, J., Nettleton, E.J., Dobson, C.M., and Robinson, C.V. (2000) Formation of insulin amyloid fibrils followed by FTIR simultaneously with CD and electron microscopy. Protein Sci.
: 1960-1967.CrossRefGoogle Scholar
Caughey, B.W., Dong, A., Bhat, K.S., Ernst, D., Hayes, S.F., and Caughey, W.S. (1991) Secondary structure analysis of the scrapie-associated protein PrP 27-30 in water by infrared spectroscopy [published erratum appears in Biochemistry 1991 Oct 29; 30(43): 10600]. Biochemistry
: 7672-7680.CrossRefGoogle Scholar
Dluhy, R.A., Shanmukh, S., Leapard, J.B., Kruger, P., and Baatz, J.E. (2003) Deacylated Pulmonary Surfactant Protein SP-C Transforms From alpha-Helical to Amyloid Fibril Structure via a pH-Dependent Mechanism: An Infrared Structural Investigation. Biophys. J.
: 2417-2429.CrossRefGoogle Scholar
Dobson, C.M. (2003) Protein folding and misfolding. Nature
: 884-890.CrossRefADSGoogle Scholar
Fabian, H., Szendrei, G.I., Mantsch, H.H., and Otvos, L., Jr. (1993) Comparative analysis of human and Dutch-type Alzheimer β-amyloid peptides by infrared spectroscopy and circular dichroism. Biochem. Biophys. Res. Commun.
: 232-239.CrossRefGoogle Scholar
Gasset, M., Baldwin, M.A., Fletterick, R.J., and Prusiner, S.B. (1993) Perturbation of the secondary structure of the scrapie prion protein under conditions that alter infectivity. Proc. Natl. Acad. Sci. USA
: 1-5.CrossRefADSGoogle Scholar
Guijarro, J.I., Sunde, M., Jones, J.A., Campbell, I.D., and Dobson, C.M. (1998) Amyloid fibril formation by an SH3 domain. Proc. Natl. Acad. Sci. USA
: 4224-4228.CrossRefADSGoogle Scholar
Jahn, T.R. and Radford, S.E. (2005) The Yin and Yang of protein folding. FEBSD J.
: 5962-5970.CrossRefGoogle Scholar
Makin, O.S. and Serpell, L.C. (2005) Structures for amyloid fibrils. FEBS J
: 5950-5961.CrossRefGoogle Scholar
Nielsen, L., Frokjaer, S., Carpenter, J.F., and Brange, J. (2001) Studies of the structure of insulin fibrils by Fourier transform infrared (FTIR) spectroscopy and electron microscopy. J. Pharm. Sci.
: 29-37.CrossRefGoogle Scholar
Puchtler, H. and Sweat, F. (1965) Congo Red as a Stain for Fluorescence Microscopy of Amyloid. J. of Histochem.Cytochem.
: 693-694.Google Scholar
Stefani, M. and Dobson, C.M. (2003) Protein aggregation and aggregate toxicity: new insights into protein folding, misfolding diseases and biological evolution. J. Mol. Med.
: 678-699.CrossRefGoogle Scholar
Tycko, R. (2004) Progress towards a molecular-level structural understanding of amyloid fibrils. Curr. Opin. Struct. Biol.
: 96-103.CrossRefGoogle Scholar
Virchow, R. (1854) Zur Celluslose-Frage. Virchows Arch.
: 415-426.Google Scholar
Westermark, P. (2005) Aspects on human amyloid forms and their fibril polypeptides. FEBS J.
: 5942-5949.CrossRefGoogle Scholar
Whittingham, J.L., Scott, D.J., Chance, K., Wilson, A., Finch, J., Brange, J., and Dodson, G.G. (2002) Insulin at pH 2: Structural analysis of the conditions promoting insulin fibre formation. J. Mol. Biol.
: 479-490.CrossRefGoogle Scholar
Zurdo, J., Guijarro, J.I., Jimenez, J.L., Saibil, H.R., and Dobson, C.M. (2001) Dependence on solution conditions of aggregation and amyloid formation by an SH3 domain. J. Mol. Biol.
: 325-340.CrossRefGoogle Scholar