4HIC

Crystal structure of the potential transfer protein TraK from Gram-positive conjugative plasmid pIP501

Summary for 4HIC

• Entry DOI: 10.2210/pdb4hic/pdb
• Descriptor: TraK (1 entity in total)
• Functional Keywords: gram-positive, type-iv secretion, pip501, anti-parallel beta-sheets, unknown function
• Biological source: Enterococcus faecalis
• Total number of polymer chains: 2
• Total formula weight: 61287.03

Authors

Goessweiner-Mohr, N.,Keller, W. (deposition date: 2012-10-11, release date: 2014-01-22, Last modification date: 2024-02-28)

Primary citation

Goessweiner-Mohr, N.,Fercher, C.,Arends, K.,Birner-Gruenberger, R.,Laverde-Gomez, D.,Huebner, J.,Grohmann, E.,Keller, W.
The type IV secretion protein TraK from the Enterococcus conjugative plasmid pIP501 exhibits a novel fold
Acta Crystallogr.,Sect.D, 70:1124-1135, 2014

PubMed Abstract: Conjugative plasmid transfer presents a serious threat to human health as the most important means of spreading antibiotic resistance and virulence genes among bacteria. The required direct cell-cell contact is established by a multi-protein complex, the conjugative type IV secretion system (T4SS). The conjugative core complex spans the cellular envelope and serves as a channel for macromolecular secretion. T4SSs of Gram-negative (G-) origin have been studied in great detail. In contrast, T4SSs of Gram-positive (G+) bacteria have only received little attention thus far, despite the medical relevance of numerous G+ pathogens (e.g. enterococci, staphylococci and streptococci). This study provides structural information on the type IV secretion (T4S) protein TraK of the G+ broad host range Enterococcus conjugative plasmid pIP501. The crystal structure of the N-terminally truncated construct TraKΔ was determined to 3.0 Å resolution and exhibits a novel fold. Immunolocalization demonstrated that the protein localizes to the cell wall facing towards the cell exterior, but does not exhibit surface accessibility. Circular dichroism, dynamic light scattering and size-exclusion chromatography confirmed the protein to be a monomer. With the exception of proteins from closely related T4SSs, no significant sequence or structural relatives were found. This observation marks the protein as a very exclusive, specialized member of the pIP501 T4SS.

PubMed: 24699656
DOI: 10.1107/S1399004714001606

Experimental method

X-RAY DIFFRACTION (3.001 Å)