4DI3

Crystal structure of a 2:1 complex of Treponema pallidum TatP(T) (Tp0957) bound to TatT (Tp0956)

Summary for 4DI3

• Entry DOI: 10.2210/pdb4di3/pdb
• Related: 3DI4 3U64 3U65
• Descriptor: TatP(T) (Tp0957), TatT (Tp0956) (2 entities in total)
• Functional Keywords: protein-protein complex, trap transporter, tpat, transport protein
• Biological source: Treponema pallidum subsp. pallidum; More
• Total number of polymer chains: 5
• Total formula weight: 173705.91

Authors

Brautigam, C.A.,Deka, R.K.,Norgard, M.V. (deposition date: 2012-01-30, release date: 2012-05-23, Last modification date: 2023-09-13)

Primary citation

Brautigam, C.A.,Deka, R.K.,Schuck, P.,Tomchick, D.R.,Norgard, M.V.
Structural and Thermodynamic Characterization of the Interaction between Two Periplasmic Treponema pallidum Lipoproteins that are Components of a TPR-Protein-Associated TRAP Transporter (TPAT).
J.Mol.Biol., 420:70-86, 2012

PubMed Abstract: Tripartite ATP-independent periplasmic transporters (TRAP-Ts) are bacterial transport systems that have been implicated in the import of small molecules into the cytoplasm. A newly discovered subfamily of TRAP-Ts [tetratricopeptide repeat-protein associated TRAP transporters (TPATs)] has four components. Three are common to both TRAP-Ts and TPATs: the P component, a ligand-binding protein, and a transmembrane symporter apparatus comprising the M and Q components (M and Q are sometimes fused to form a single polypeptide). TPATs are distinguished from TRAP-Ts by the presence of a unique protein called the "T component". In Treponema pallidum, this protein (TatT) is a water-soluble trimer whose protomers are each perforated by a pore. Its respective P component (TatP(T)) interacts with the TatT in vitro and in vivo. In this work, we further characterized this interaction. Co-crystal structures of two complexes between the two proteins confirm that up to three monomers of TatP(T) can bind to the TatT trimer. A putative ligand-binding cleft of TatP(T) aligns with the pore of TatT, strongly suggesting ligand transfer between T and P(T). We used a combination of site-directed mutagenesis and analytical ultracentrifugation to derive thermodynamic parameters for the interactions. These observations confirm that the observed crystallographic interface is recapitulated in solution. These results prompt a hypothesis of the molecular mechanism(s) of hydrophobic ligand transport by the TPATs.

PubMed: 22504226
DOI: 10.1016/j.jmb.2012.04.001

Experimental method

X-RAY DIFFRACTION (3.05 Å)