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Infrared spectroscopy of human amyloid fibrils and immunogolbulin proteins
Author(s) -
Termine J. D.,
Eanes E. D.,
Ein D.,
Glenner G. G.
Publication year - 1972
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1972.360110512
Subject(s) - antiparallel (mathematics) , chemistry , fibril , beta sheet , infrared spectroscopy , protein secondary structure , crystallography , amyloid (mycology) , immunoglobulin light chain , molecule , protein structure , biochemistry , antibody , organic chemistry , inorganic chemistry , physics , quantum mechanics , magnetic field , immunology , biology
The presence of the antiparallel‐β‐pleated sheet coformation io isolated human amyloid protein fibrils has been confirmed by infrared spectroscopy. In most amyloid samples, this conformation was enhanced by acidic solution conditions. Infrared spectroscopy (Amide I and Amide V absorption bands) and x‐ray diffraction methods were also used to examine the immunoglobulin molecule for solid state‐β‐structure. It was found that both heavy chains and Bence Jones proteins exhibited some β‐pleated sheet content upon acid and/or heat treatment. Furthermore, pepsin digests comprising either the variable‐rich region (Fd′) of the immunloglobulin heavy chain or in particular, filamentous variable segments of κ and λ Bence Jones proteins were, as isolated, very similar to amyloid in β‐structure content. Data from other immunoglobulin‐derived sample did not exhibit extensive β‐pleated sheet content. On the other hand, most amyliod and immunoglobulin‐derived samples did display some β‐structure when cast from 50% HCOOH solution. Under these conditions, however, filamentous light chain‐variable segments exhibited well‐defined infrared patterns rich in antiparallel‐β‐pleated sheet structure and gave a “cross‐β” x‐ray diffraction pattern.