Going deep into protein secondary structure with synchrotron radiation circular dichroism spectroscopy
Circular dichroism (CD) spectroscopy is a fast, powerful, well-established, and widely used analytical technique in the biophysical and structural biology community to study protein secondary structure and to track changes in protein conformation in different environments. The use of the intense light of a synchrotron beam as the light source for collecting CD measurements has emerged as an enhanced method, known as synchrotron radiation circular dichroism (SRCD) spectroscopy, that has several advantages over the conventional CD method, including a significant spectral range extension for data collection, deeper access to the lower limit (cut-off) of conventional CD spectroscopy, an improved signal-to-noise ratio to increase accuracy in the measurements, and the possibility to collect measurements in highly absorbing solutions. In this review, we discuss different applications of the SRCD technique by researchers from Latin America. In this context, we specifically look at the use of this method for examining the secondary structure and conformational behavior of proteins belonging to the four main classes of the hierarchical protein domain classification CATH (Class, Architecture, Topology, Homology) database, focusing on the advantages and improvements associated with SRCD spectroscopy in terms of characterizing proteins composed of different structural elements.
KeywordsCircular dichroism spectroscopy Conformational changes Protein conformation Protein secondary structure Synchrotron radiation circular dichroism spectroscopy
JLSL and PSK are grateful for beamtime access at the AU-CD beamline at the ASTRID2 (Aarhus, Denmark) and at the UV-CD12 at t he ANKA (Karlsruhe, Germany) synchrotrons. All authors thank Prof. BA Wallace for supporting the implementation of SRCD in Brazil and for helpful discussions.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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