The type IV secretion protein TraK from the Enterococcus conjugative plasmid pIP501 exhibits a novel fold.
Acta Crystallogr D Biol Crystallogr
; 70(Pt 4): 1124-35, 2014 Apr.
Article
em En
| MEDLINE
| ID: mdl-24699656
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 3.0â
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Plasmídeos
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Proteínas de Bactérias
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Enterococcus faecalis
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Proteínas de Ligação a DNA
Idioma:
En
Revista:
Acta Crystallogr D Biol Crystallogr
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Áustria