Lassaux Patricia, Conchillo-Solé Oscar, Manjasetty Babu A, Yero Daniel, Perletti Lucia, Belrhali Hassan, Daura Xavier, Gourlay Louise J, Bolognesi Martino
Department of Biosciences, University of Milan, Milan, Italy.
Institute of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona, Bellaterra, Spain.
PLoS One. 2014 Apr 11;9(4):e94981. doi: 10.1371/journal.pone.0094981. eCollection 2014.
Type IV pili are surface-exposed filaments and bacterial virulence factors, represented by the Tfpa and Tfpb types, which assemble via specific machineries. The Tfpb group is further divided into seven variants, linked to heterogeneity in the assembly machineries. Here we focus on PilO2(Bp), a protein component of the Tfpb R64 thin pilus variant assembly machinery from the pathogen Burkholderia pseudomallei. PilO2(Bp) belongs to the PF06864 Pfam family, for which an improved definition is presented based on newly derived Hidden Markov Model (HMM) profiles. The 3D structure of the N-terminal domain of PilO2(Bp) (N-PilO2(Bp)), here reported, is the first structural representative of the PF06864 family. N-PilO2(Bp) presents an actin-like ATPase fold that is shown to be present in BfpC, a different variant assembly protein; the new HMM profiles classify BfpC as a PF06864 member. Our results provide structural insight into the PF06864 family and on the Type IV pili assembly machinery.
IV型菌毛是表面暴露的细丝和细菌毒力因子，以Tfpa和Tfpb类型为代表，它们通过特定的机制组装。Tfpb组进一步分为七个变体，这与组装机制的异质性有关。在这里，我们聚焦于PilO2(Bp)，它是来自病原体类鼻疽伯克霍尔德菌的Tfpb R64细菌毛变体组装机制的一种蛋白质成分。PilO2(Bp)属于PF06864 Pfam家族，基于新推导的隐马尔可夫模型(HMM)概况给出了该家族的改进定义。本文报道的PilO2(Bp) N端结构域(N-PilO2(Bp))的三维结构是PF06864家族的首个结构代表。N-PilO2(Bp)呈现出一种肌动蛋白样ATP酶折叠结构，在另一种不同的变体组装蛋白BfpC中也有发现；新的HMM概况将BfpC归类为PF06864家族成员。我们的结果为PF06864家族以及IV型菌毛组装机制提供了结构上的见解。
