Figure 1.

Genetic organization of the T2SS clusters. The name of each T2SS gene cluster is shown in brackets beside the name of the bacterial species. Each gene is represented by an arrow and ‘core’ genes present in all T2SS clusters are represented in colour. The gspE_R, F_S, L_Y and M_Z genes encoding components of the inner membrane platform are shown in green; the gspG_T, H_U, I_V, J_W and K_X genes encoding pseudopilins and gspO_A gene encoding the prepilin peptidase are shown in orange; the gspD_Q gene encoding the secretin is shown in blue; the gspC_P gene encoding the trans-periplasmic protein is represented in shaded green and blue tones because GspC_P is a component of the inner membrane surface interacting with secretin. The gspA, B, N and S genes that are not considered to be core components of the T2SS are represented in white.