NMR resonance assignments for the GSPII-C domain of the PilF ATPase from Thermus thermophilus in complex with c-di-GMP.

The natural transformation system of the thermophilic bacterium Thermus thermophilus is one of the most efficient DNA transport systems in terms of DNA uptake rate and promiscuity. The DNA transporter of T. thermophilus plays an important role in interdomain DNA transfer in hot environments. PilF is the traffic ATPase that provides the energy for the assembly of the DNA translocation machinery and the functionally linked type IV pilus system in T. thermophilus. In contrast to other known traffic ATPases， the N-terminal region of PilF harbors three consecutive domains with homology to general secretory pathway II (GSPII) domains. These GSPII-like domains influence pilus assembly， twitching motility and transformation efficiency. A structural homolog of the PilF GSPII-like domains， the N-terminal domain of the traffic ATPase MshE from Vibrio cholerae， was recently crystallized in complex with the bacterial second messenger c-di-GMP. In order to study the consequences of c-di-GMP binding on the three-dimensional architecture of PilF， we initiated structural studies on the PilF GSPII-like domains. Here， we present the H， C and N chemical shift assignments for the isolated PilF GSPII-C domain from T. thermophilus in complex with c-di-GMP. In addition， the structural dynamics of the complex was investigated in an {H}，N-hetNOE experiment.