Crystal structure of Mycobacterium tuberculosis SecA, a preprotein translocating ATPase

Vivek Sharma, Arulandu Arockiasamy, Donald R. Ronning, Christos G. Savva, Andreas Holzenburg, Miriam Braunstein, William R. Jacobs, James C. Sacchettini

Research output: Contribution to journalArticlepeer-review

157 Scopus citations


In bacteria, the majority of exported proteins are translocated by the Sec system, which recognizes the signal sequence of a preprotein and uses ATP and the proton motive force to mediate protein translocation across the cytoplasmic membrane. SecA is an essential protein component of this system, containing the molecular motor that facilitates translocation. Here we report the threedimensional structure of the SecA protein of Mycobacterium tuberculosis. Each subunit of the homodimer contains a "motor" domain and a translocation domain. The structure predicts that SecA can interact with the SecYEG pore and function as a molecular ratchet that uses ATP hydrolysis for physical movement of the preprotein. Knowledge of this structure provides a framework for further elucidation of the translocation process.

Original languageEnglish (US)
Pages (from-to)2243-2248
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number5
StatePublished - Mar 4 2003

ASJC Scopus subject areas

  • General


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