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A Different hIAPP Polymorph Is Observed in Human Serum Than in Aqueous Buffer: Demonstration of a New Method for Studying Amyloid Fibril Structure Using Infrared Spectroscopy.
Fields, Caitlyn R; Dicke, Sidney S; Petti, Megan K; Zanni, Martin T; Lomont, Justin P.
Afiliación
  • Fields CR; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
  • Dicke SS; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
  • Petti MK; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
  • Zanni MT; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
  • Lomont JP; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
J Phys Chem Lett ; 11(15): 6382-6388, 2020 Aug 06.
Article en En | MEDLINE | ID: mdl-32706257
There is enormous interest in measuring amyloid fibril structures, but most structural studies measure fibril formation in vitro using aqueous buffer. Ideally, one would like to measure fibril structure and mechanism under more physiological conditions. Toward this end, we have developed a method for studying amyloid fibril structure in human serum. Our approach uses isotope labeling, antibody depletion of the most abundant proteins (albumin and IgG), and infrared spectroscopy to measure aggregation in human serum with reduced protein content. Reducing the nonamyloid protein content enables the measurements by decreasing background signals but retains the full composition of salts, sugars, metal ions, etc. that are naturally present but usually missing from in vitro studies. We demonstrate the method by measuring the two-dimensional infrared (2D IR) spectra of isotopically labeled human islet amyloid polypeptide (hIAPP or amylin). We find that the fibril structure of hIAPP formed in serum differs from that formed via aggregation in aqueous buffer at residues Gly24 and Ala25, which reside in the putative "amyloidogenic core" or FGAIL region of the sequence. The spectra are consistent with extended parallel stacks of strands consistent with ß-sheet-like structure, rather than a partially disordered loop that forms in aqueous buffer. These experiments provide a new method for using infrared spectroscopy to monitor the structure of proteins under physiological conditions and reveal the formation of a significantly different polymorph structure in the most important region of hIAPP.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Fragmentos de Péptidos / Espectrofotometría Infrarroja / Amiloide Límite: Humans Idioma: En Revista: J Phys Chem Lett Año: 2020 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Fragmentos de Péptidos / Espectrofotometría Infrarroja / Amiloide Límite: Humans Idioma: En Revista: J Phys Chem Lett Año: 2020 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos