Acknowledgements The authors wish to thank Prof. selleckchem Hiroshi Nikaido (Department of Molecular and Cell Biology, University of California, Berkeley, California, U.S.A) and Prof. Michael Niederweis for kindly providing the M. smegmatis mutant strains used in this work and to Prof. Winfried V. Kern (Center for Infectious Diseases and Travel Medicine, University Hospital, Freiburg, Germany) for valuable suggestions and scientific discussions. This work was supported by grants EU-FSE/FEDER-PTDC/BIA-MIC/71280/2006, EU-FSE/FEDER-PTDC/BIA-MIC/105509/2008 and EU-FSE/FEDER-PTDC/SAU-FCF/102807/2008 provided by Fundação para a Ciência e a Tecnologia (FCT) of Portugal. L. Rodrigues was supported
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