Retraction

The recently reported structure of Sav1866 (4) indicated that our MsbA structures (1, 2, 5) were incorrect in both the hand of the structure and the topology. Thus, our biological interpretations based on these inverted models for MsbA are invalid.

An in-house data reduction program introduced a change in sign for anomalous differences. This program, which was not part of a conventional data processing package, converted the anomalous pairs (I+ and I-) to (F- and F+), thereby introducing a sign change. As the diffraction data collected for each set of MsbA crystals and for the EmrE crystals were processed with the same program, the structures reported in (1-3, 5, 6) had the wrong hand.

The error in the topology of the original MsbA structure was a consequence of the low resolution of the data as well as breaks in the electron density for the connecting loop regions. Unfortunately, the use of the multicopy refinement procedure still allowed us to obtain reasonable refinement values for the wrong structures.

The Protein Data Bank (PDB) files 1JSQ, 1PF4, and 1Z2R for MsbA and 1S7B and 2F2M for EmrE have been moved to the archive of obsolete PDB entries. The MsbA and EmrE structures will be recalculated from the original data using the proper sign for the anomalous differences, and the new C coordinates and structure factors will be deposited.

We very sincerely regret the confusion that these papers have caused and, in particular, subsequent research efforts that were unproductive as a result of our original findings.

Geoffrey Chang
Department of Molecular Biology
The Scripps Research Institute
La Jolla, CA 92037, USA

Christopher B. Roth
Department of Molecular Biology
The Scripps Research Institute
La Jolla, CA 92037, USA

Christopher L. Reyes
Department of Molecular Biology
The Scripps Research Institute
La Jolla, CA 92037, USA

Owen Pornillos
Department of Molecular Biology
The Scripps Research Institute
La Jolla, CA 92037, USA

Yen-Ju Chen
Department of Molecular Biology
The Scripps Research Institute
La Jolla, CA 92037, USA

Andy P. Chen
Department of Molecular Biology
The Scripps Research Institute
La Jolla, CA 92037, USA

References

1. G. Chang, C. B. Roth, Science 293, 1793 (2001).
2. C. L. Reyes, G. Chang, Science 308, 1028 (2005).
3. O. Pornillos, Y.-J. Chen, A. P. Chen, G. Chang, Science 310, 1950 (2005).
4. R. J. Dawson, K. P. Locher, Nature 443, 180 (2006).
5. G. Chang, J. Mol. Biol. 330, 419 (2003).
6. C. Ma, G. Chang, Proc. Natl. Acad. Sci. U.S.A. 101, 2852 (2004).