The interaction of TraW and TrbC is required to facilitate conjugation in F-like plasmids

Protein interactions within and between two F‐type type IV secretion systems

“…Since two‐hybrid systems can give both false‐negative and false‐positive results, we aimed to further validate our findings with other methods. For many of the interactions observed in this study, some evidence for the interaction between the studied proteins or homologs from other T4SSs can be found in the literature (Das et al ., 1997; Das and Xie, 2000; Gilmour et al ., 2001; Harris et al ., 2001; Ding et al ., 2002; Harris and Silverman, 2004; Chandran et al ., 2009; Fronzes et al ., 2009; Sivanesan et al ., 2010; Low et al ., 2014; Ramsey et al ., 2014; Casu et al ., 2016; Oliveira et al ., 2016; Shala‐Lawrence et al ., 2018; Hu et al ., 2019). However, only limited evidence exists for interactions between OMCC proteins homologs (TraB, TraV, and TraK) and F‐type‐specific periplasmic proteins (Arutyunov et al ., 2010), and the function of the F‐type‐specific periplasmic proteins is poorly understood.…”

“…For periplasmic proteins cloned only in the BACTH‐TM system, we observed interactions between TraW and TrbC from both the N. gonorrhoeae T4SS and the F‐plasmid T4SS. In several F‐type T4SSs, TrbC proteins are fused to the N‐terminus of TraW, and TrbC F and TraW F were found to co‐purify, indicating that the TraW/TrbC interaction is important for F‐type T4SSs (Shala‐Lawrence et al ., 2018). These results indicate that BACTH‐TM system can be used successfully to study periplasmic protein interactions.…”

Protein Dynamics in F-like Bacterial Conjugation

“…This shows that TraW plays an essential role in the pilus extension process; however, its protein interactions are not fully understood. It is hypothesized that TraW interacts with its neighboring protein TrbC [ 97 ].…”

“…Both TraW and TrbC are very similar in their localization and function, and in some systems, these proteins are expressed as a single polypeptide, indicating that cooperative function may occur between TraW and TrbC. Previous studies performed using conjugative mating assays showed that an interaction between the NTD of TraW and the CTD of TrbC was essential for conjugation to occur [ 97 ]. It is possible that this same interaction is required for the assembly of the pilus.…”

“…It is possible that this same interaction is required for the assembly of the pilus. When examining sequence alignments of these two proteins and comparing systems that produce two separate proteins and ones that produce one single polypeptide, it is clear that TrbC mimics the NTD of the single polypeptide while TraW mimics the CTD, further indicating an interaction between the CTD of TrbC and the NTD of TraW [ 97 ].…”