The FtsK-like motor TraB is a DNA-dependent ATPase that forms higher-order assemblies.
J Biol Chem
; 294(13): 5050-5059, 2019 03 29.
Article
en En
| MEDLINE
| ID: mdl-30723158
ABSTRACT
TraB is an FtsK-like DNA translocase responsible for conjugative plasmid transfer in mycelial Streptomyces Unlike other conjugative systems, which depend on a type IV secretion system, Streptomyces requires only TraB protein to transfer the plasmid as dsDNA. The γ-domain of this protein specifically binds to repeated 8-bp motifs on the plasmid sequence, following a mechanism that is reminiscent of the FtsK/SpoIIIE chromosome segregation system. In this work, we purified and characterized the enzymatic activity of TraB, revealing that it is a DNA-dependent ATPase that is highly stimulated by dsDNA substrates. Interestingly, we found that unlike the SpoIIIE protein, the γ-domain of TraB does not confer sequence-specific ATPase stimulation. We also found that TraB binds G-quadruplex DNA structures with higher affinity than TraB-recognition sequences (TRSs). An EM-based structural analysis revealed that TraB tends to assemble as large complexes comprising four TraB hexamers, which might be a prerequisite for DNA translocation across cell membranes. In summary, our findings shed light on the molecular mechanism used by the DNA-translocating motor TraB, which may be shared by other membrane-associated machineries involved in DNA binding and translocation.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Streptomyces
/
Proteínas Bacterianas
/
Adenosina Trifosfatasas
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
J Biol Chem
Año:
2019
Tipo del documento:
Article