NMR resonance assignments for the GSPII-B domain of the traffic ATPase PilF from Thermus thermophilus in the apo and the c-di-GMP-bound state

The PilF protein from the thermophilic bacterium Thermus thermophilus is a traffic ATPase powering the assembly of the DNA translocation machinery as well as of type 4 pili. Thereby PilF mediates the natural transformability of T. thermophilus. PilF contains a C-terminal ATPase domain and three N-terminal domains with partial homology to so-called general secretory pathway II (GSPII) domains. These three GSPII domains (GSPII-A, GSPII-B and GSPII-C) are essential for pilus assembly and twitching motility. They show varying degrees of sequence homology to the N-terminal domain of the ATPase MshE from Vibrio cholerae which binds the bacterial second messenger molecule c-di-GMP. NMR experiments demonstrate that the GSPII-B domain of PilF also binds c-di-GMP with high affinity and forms a 1:1 complex in slow exchange on the NMR time scale. As a prerequisite for structural studies of c-di-GMP binding to the GSPII-B domain of T. thermophilus PilF we present here the NMR resonance assignments for the apo and the c-di-GMP bound state of GSPII-B. In addition, we map the binding site for c-di-GMP on the GSPII-B domain using chemical shift perturbation data and compare the dynamics of the apo and the c-di-GMP-bound state of the GSPII-B domain based on {H-1},N-15-hetNOE data.