Title: External cavity-quantum cascade laser infrared spectroscopy for secondary structure analysis of proteins at low concentrations
Language: English
Authors: Lendl, Bernhard  
Schwaighofer, Andreas  
Alcaráz, Mirta Raquel 
Araman, Can 
Goicoechea, Héctor
Issue Date: 2016
Journal: Scientific Reports
ISSN: 2045-2322
Fourier transform infrared (FTIR) and circular dichroism (CD) spectroscopy are analytical techniques employed for the analysis of protein secondary structure. The use of CD spectroscopy is limited to low protein concentrations (<2 mg ml−1), while FTIR spectroscopy is commonly used in a higher concentration range (>5 mg ml−1). Here we introduce a quantum cascade laser (QCL)-based IR transmission setup for analysis of protein and polypeptide secondary structure at concentrations as low as 0.25 mg ml−1 in deuterated buffer solution. We present dynamic QCL-IR spectra of the temperature-induced α-helix to β-sheet transition of poly-L-lysine. The concentration dependence of the α-β transition temperature between 0.25 and 10 mg ml−1 was investigated by QCL-IR, FTIR and CD spectroscopy. By using QCL-IR spectroscopy it is possible to perform IR spectroscopic analysis in the same concentration range as CD spectroscopy, thus enabling a combined analysis of biomolecules secondary structure by CD and IR spectroscopy.
Keywords: Bioanalytical chemistry; Infrared spectroscopy; Protein folding
DOI: 10.1038/srep33556
Library ID: AC11360473
URN: urn:nbn:at:at-ubtuw:3-2117
Organisation: E164 - Institut für Chemische Technologien und Analytik 
Publication Type: Article
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