2MI2

Solution structure of the E. coli TatB protein in DPC micelles

Summary for 2MI2

• Entry DOI: 10.2210/pdb2mi2/pdb
• NMR Information: BMRB: 19618
• Descriptor: Sec-independent protein translocase protein TatB (1 entity in total)
• Functional Keywords: transport protein
• Biological source: Escherichia coli
• Cellular location: Cell membrane; Single-pass membrane protein (By similarity): E2QI32
• Total number of polymer chains: 1
• Total formula weight: 12343.27

Authors

Zhang, Y.,Wang, L.,Hu, Y.,Jin, C. (deposition date: 2013-12-08, release date: 2014-04-30, Last modification date: 2024-05-15)

Primary citation

Zhang, Y.,Wang, L.,Hu, Y.,Jin, C.
Solution structure of the TatB component of the twin-arginine translocation system.
Biochim.Biophys.Acta, 1838:1881-1888, 2014

PubMed Abstract: The twin-arginine protein transport (Tat) system translocates fully folded proteins across lipid membranes. In Escherichia coli, the Tat system comprises three essential components: TatA, TatB and TatC. The protein translocation process is proposed to initiate by signal peptide recognition and substrate binding to the TatBC complex. Upon formation of the TatBC-substrate protein complex, the TatA subunits are recruited and form the protein translocation pore. Experimental evidences suggest that TatB forms a tight complex with TatC at 1:1 molar ratio and the TatBC complex contains multiple copies of both proteins. Cross-linking experiments demonstrate that TatB functions in tetrameric units and interacts with both TatC and substrate proteins. However, structural information of the TatB protein is still lacking, and its functional mechanism remains elusive. Herein, we report the solution structure of TatB in DPC micelles determined by Nuclear Magnetic Resonance (NMR) spectroscopy. Overall, the structure shows an extended 'L-shape' conformation comprising four helices: a transmembrane helix (TMH) α1, an amphipathic helix (APH) α2, and two solvent exposed helices α3 and α4. The packing of TMH and APH is relatively rigid, whereas helices α3 and α4 display notably higher mobility. The observed floppiness of helices α3 and α4 allows TatB to sample a large conformational space, thus providing high structural plasticity to interact with substrate proteins of different sizes and shapes.

PubMed: 24699374
DOI: 10.1016/j.bbamem.2014.03.015

Experimental method

SOLUTION NMR