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Determination of the secondary structure of proteins in different environments by FTIR‐ATR spectroscopy and PLS regression
Author(s) -
Wang Yeqiu,
Boysen Reinhard I.,
Wood Bayden R.,
Kansiz Mustafa,
McNaughton Don,
Hearn Milton T. W.
Publication year - 2008
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.21022
Subject(s) - sorbent , chemistry , adsorption , protein secondary structure , random coil , fourier transform infrared spectroscopy , chromatography , crystallography , organic chemistry , chemical engineering , biochemistry , engineering
The secondary structures of proteins (α‐helical, β‐sheet, β‐turn, and random coil) in the solid state and when bound to polymer beads, containing immobilized phenyl and butyl ligands such as those as commonly employed in hydrophobic interaction chromatography, have been investigated using FTIR‐ATR spectroscopy and partial least squares (PLS) methods. Proteins with known structural features were used as models, including 12 proteins in the solid state and 7 proteins adsorbed onto the hydrophobic surfaces. A strong PLS correlation was achieved between predictions derived from the experimental data for 4 proteins adsorbed onto the phenyl‐modified beads and reference data obtained from the X‐ray crystallographic structures with r 2 values of 0.9974, 0.9864, 0.9924, and 0.9743 for α‐helical, β‐sheet, β‐turn, and random coiled structures, respectively. On the other hand, proteins adsorbed onto the butyl sorbent underwent greater secondary structural changes compared to the phenyl sorbent as evidenced from the poorer PLS r 2 values (r 2 are 0.9658, 0.9106, 0.9571, and 0.9340). The results thus indicate that the secondary structures for these proteins were more affected by the butyl sorbent, whereas the secondary structure remains relatively unchanged for the proteins adsorbed onto the phenyl sorbent. This study has important ramifications for understanding the nature of protein secondary structural changes following adsorption onto hydrophobic sorbent surfaces. This knowledge could also enable the development of useful protocols for enhancing the chromatographic purification of proteins in their native bioactive states. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 895–905, 2008. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com