A group of authors in China has lost their June 2013 paper in the European Biophysics Journal because they appear to have misinterpreted their data. The paper, “Overestimated accuracy of circular dichroism in determining protein secondary structure,” came from chemists at Fudan University in Shanghai, and purported to find that:
Circular dichroism (CD) is a spectroscopic technique widely used for estimating protein secondary structures in aqueous solution, but its accuracy has been doubted in recent work. In the present paper, the contents of nine globular proteins with known secondary structures were determined by CD spectroscopy and Fourier transform infrared spectroscopy (FTIR) in aqueous solution. A large deviation was found between the CD spectra and X-ray data, even when the experimental conditions were optimized. The content determined by FTIR was in good agreement with the X-ray crystallography data. Therefore, CD spectra are not recommended for directly calculating the content of a protein’s secondary structure.
But now comes this:
After publication of this article, concerns were raised regarding accuracy and interpretation of the presented Circular Dichroism data. To investigate these claims, the article was checked again by two additional referees, and was also discussed by members of the European Circular Dichroism Society. The investigation revealed that the Circular Dichroism aspects of the article are invalid, because the measured protein Circular Dichroism spectra are highly inaccurate, and contradict numerous published studies. Hence, the conclusions of the authors regarding the unreliability of using Circular Dichroism for protein secondary structure determination are unjustified and misleading. When confronted with these findings, the authors were unable to dispel the doubts in their experimental methods and declined the invitation to withdraw the article themselves. It could also not be clarified, why the Circular Dichroism spectra presented in this paper have anomalously low amplitudes.
As a result of these findings and the subsequent discussions, the Managing Editor of the European Biophysics Journal, Anthony Watts, has now retracted this article.
The paper has yet to be cited. We commend the EBJ on its informative retraction notice. But the editors might not want to use the same batch of reviewers again — or at least limit them to areas in which they have more expertise.
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