This family contains components of both the Type II protein secretion system (T2SS), including Type 4 pilus (T4P), and Type IV protein secretion system (T4SS) from Gram-negative bacteria. Swiss:P07169 VirB11 ATPase is a subunit of the Agrobacterium tumefaciens transfer DNA (T-DNA) transfer system, a type IV secretion pathway required for delivery of T-DNA and effector proteins to plant cells during infection [1]. The cytoplasmic T2S E ATPase is a Zn-containing protein thought to provide the mechanical force for the secretion process. T2S-E contains Walker A and B motifs, that are essential for secretion and ATPase activity. ATPase PulE and XcpR from Klebsiella oxytoca and Pseudomonas aeruginosa respectively are required for protein secretion via the T2SS. ATPase PilB is required for T4P extension [2].

1: Role of Agrobacterium VirB11 ATPase in T-pilus assembly and substrate selection. Sagulenko E, Sagulenko V, Chen J, Christie PJ; J Bacteriol 2001;183:5813-5825. PMID:11566978

2: Mutations in the consensus ATP-binding sites of XcpR and PilB eliminate extracellular protein secretion and pilus biogenesis in Pseudomonas aeruginosa. Turner LR, Lara JC, Nunn DN, Lory S; J Bacteriol. 1993;175:4962-4969. PMID:8102361