Fourier transform infrared study of proteins with parallel beta-chains.

H Susi; D M Byler

doi:10.1016/0003-9861(87)90367-5

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Fourier transform infrared study of proteins with parallel beta-chains.

H Susi·D M Byler

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Abstract

Deconvolved and second derivative Fourier transform infrared spectra of the proteins flavodoxin and triosephosphate isomerase have been obtained in the 1600 to 1700 cm-1 (amide I) region. To our knowledge these results provide the first experimental infrared data on proteins with parallel beta-chains. Characteristic absorption bands for the parallel beta-segments are observed at 1626-1639 cm-1 (strong) and close to 1675 cm-1 (weak). Previous theoretical studies based on hypothetical models with large, regular beta-sheets had suggested bands close to 1650 and 1666 cm-1. Our new assignments were confirmed by band area measurements, which yield conformational information in good agreement with results from X-ray diffraction data. The spectra were compared with corresponding spectra of concanavalin A and carboxypeptidase A. The first contains only antiparallel beta-segments, the second "mixed" beta-segments, with some strands lying antiparallel and others parallel. None of the observed amide I band frequencies assigned to parallel beta-chains occurs in the 1650 cm-1 region associated with helical segments.

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Carboxypeptidases Carboxypeptidases A Concanavalin A Flavodoxin Fourier Analysis Macromolecular Substances Models, Molecular Protein Conformation Proteins Spectrophotometry, Infrared Triose-Phosphate Isomerase Journal Article

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H Susi, D M Byler. 1987-11-01. Fourier transform infrared study of proteins with parallel beta-chains.. https://doi.org/10.1016/0003-9861(87)90367-5

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