Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Case studies of the evolution of molecular machines remain scarce. One of the most diverse and widespread homologous families of machines is the type IV filament (TFF) superfamily, comprised of type IV pili, type II secretion systems (T2SSs), archaella, and other less-well-characterized families. These families have functions including twitching motility, effector export, rotary propulsion, nutrient uptake, DNA uptake, and even electrical conductance, but it is unclear how such diversity evolved from a common ancestor. In this issue, Denise and colleagues take a significant step toward understanding evolution of the TFF superfamily by determining a global phylogeny and using it to infer an evolutionary pathway. Results reveal that the superfamily predates the divergence of Bacteria and Archaea, and show how duplications, acquisitions, and losses coincide with changes in function. Surprises include that tight adherence (Tad) pili were horizontally acquired from Archaea and that T2SSs were relatively recently repurposed from type IV pili. Results also enable better understanding of the function of the ATPase family that powers the superfamily. The study highlights the role of tinkering by exaptation-the repurposing of pre-existing functions for new roles-in the diversification of molecular machines.
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PMID:Evolution of a family of molecular Rube Goldberg contraptions. 3132 28

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 {¹H},¹⁵N-hetNOE data.
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PMID: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. 3143

The bacterial flagellum is one of the best-studied surface-attached appendages in bacteria. Flagellarassembly in vivo is promoted by its own protein export apparatus, a type III secretion system (T3SS) in pathogenic bacteria. Lysobacter enzymogenes OH11 is a non-flagellated soil bacterium that utilizes type IV pilus (T4P)-driven twitching motility to prey upon nearby fungi for food. Interestingly, the strain OH11 encodes components homologous to the flagellar type III protein apparatus (FT3SS) on its genome, but it remains unknown whether this FT3SS-like system is functional. Here, we report that, despite the absence of flagella, the FT3SS homologous genes are responsible not only for the export of the heterologous flagellin in strain OH11 but also for twitching motility. Blocking the FT3SS-like system by in-frame deletion mutations in either flhB or fliI abolished the secretion of heterologous flagellin moleculesinto the culture medium, indicating that the FT3SS is functional in strain OH11. A deletion of flhA, flhB, fliI, or fliR inhibited T4P-driven twitching motility, whereas neither that of fliP nor fliQ did, suggesting that FlhA, FlhB, FliI, and FliR may obtain a novel function to modulate the twitching motility. The flagellar FliI ATPase was required for the secretion of the major pilus subunit, PilA, suggesting that FliI would have evolved to act as a PilB-like pilus ATPase. These observations lead to a plausible hypothesis that the non-flagellated L. enzymogenes OH11 could preserve FT3SS-like genes for acquiring a distinct function to regulate twitching motility associated with its predatory behavior.
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PMID:The Homologous Components of Flagellar Type III Protein Apparatus Have Acquired a Novel Function to Control Twitching Motility in a Non-Flagellated Biocontrol Bacterium. 3239 34


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