Molecular analysis of archaeal flagellins: similarity to the type IV pilin – transport superfamily widespread in bacteria

1994 ◽  
Vol 40 (1) ◽  
pp. 67-71 ◽  
Author(s):  
David M. Faguy ◽  
Ken F. Jarrell ◽  
John Kuzio ◽  
Martin L. Kalmokoff

Ultrastructural, biochemical and genetic evidence has shown that the flagella and flagellin proteins from members of the archaea are distinct from their bacterial counterparts. The most important evidence is the sequence dissimilarity between archaeal and bacterial flagellins. We report here similarity between archaeal flagellins and members of the bacterial type IV pilin – transport superfamily. In addition to sequence similarity, the archaeal flagellins and the type IV pilin – transport superfamily share an unusual signal sequence cleavage site and may have functional parallels. This relationship has important implications for the assembly and biogenesis of archaeal flagella.Key words: flagellin, type IV pilin, homology, general secretion proteins, archaea.

2010 ◽  
Vol 192 (12) ◽  
pp. 3093-3102 ◽  
Author(s):  
Manuela Tripepi ◽  
Saheed Imam ◽  
Mechthild Pohlschröder

ABSTRACT Although the genome of Haloferax volcanii contains genes (flgA1-flgA2) that encode flagellins and others that encode proteins involved in flagellar assembly, previous reports have concluded that H. volcanii is nonmotile. Contrary to these reports, we have now identified conditions under which H. volcanii is motile. Moreover, we have determined that an H. volcanii deletion mutant lacking flagellin genes is not motile. However, unlike flagella characterized in other prokaryotes, including other archaea, the H. volcanii flagella do not appear to play a significant role in surface adhesion. While flagella often play similar functional roles in bacteria and archaea, the processes involved in the biosynthesis of archaeal flagella do not resemble those involved in assembling bacterial flagella but, instead, are similar to those involved in producing bacterial type IV pili. Consistent with this observation, we have determined that, in addition to disrupting preflagellin processing, deleting pibD, which encodes the preflagellin peptidase, prevents the maturation of other H. volcanii type IV pilin-like proteins. Moreover, in addition to abolishing swimming motility, and unlike the flgA1-flgA2 deletion, deleting pibD eliminates the ability of H. volcanii to adhere to a glass surface, indicating that a nonflagellar type IV pilus-like structure plays a critical role in H. volcanii surface adhesion.


2018 ◽  
Author(s):  
R. Zöllner ◽  
T. Cronenberg ◽  
N. Kouzel ◽  
A. Welker ◽  
M. Koomey ◽  
...  

AbstractBacterial type 4 pili (T4P) are extracellular polymers that initiate the formation of microcolonies and biofilms. T4P continuously elongate and retract. These pilus dynamics crucially affects the local order, shape, and fluidity of microcolonies. The major pilin subunit of the T4P bears multiple post-translational modifications. By interfering with different steps of the pilin glycosylation and phosphoform modification pathways, we investigated the effect of pilin post-translational modification on the shape and dynamics of microcolonies formed by Neisseria gonorrhoeae. Deleting the phosphotransferase responsible for phosphoethanolamine modification at residue serine 68 (S68) inhibits shape relaxations of microcolonies after pertubation and causes bacteria carrying the phosphoform modification to segregate to the surface of mixed colonies. We relate these mesoscopic phenotypes to increased attractive forces generated by T4P between cells. Moreover, by deleting genes responsible for the pilin glycan structure, we show that the number of saccharides attached at residue serine 63 (S63) affect the ratio between surface tension and viscosity and cause sorting between bacteria carrying different pilin glycoforms. We conclude that different pilin post-translational modifications moderately affect the attractive forces between bacteria but have severe effects on the materials properties of microcolonies.


Microbiology ◽  
2003 ◽  
Vol 149 (5) ◽  
pp. 1249-1255 ◽  
Author(s):  
Marie-Annick Lety ◽  
Claude Frehel ◽  
Jean-luc Beretti ◽  
Patrick Berche ◽  
Alain Charbit

Listeriolysin O (LLO, hly-encoded), a major virulence factor secreted by the bacterial pathogen Listeria monocytogenes, is synthesized as a precursor of 529 residues. To impair LLO secretion, the four residues of the predicted signal sequence cleavage site (EA-KD) were deleted and the mutant LLO protein was expressed in a hly-negative derivative of L. monocytogenes. Unexpectedly, the mutant protein was secreted in normal amounts in the culture supernatant and was fully haemolytic. N-terminal sequencing of the secreted LLO molecule revealed that N-terminal processing of the preprotein occurred three residues downstream of the natural cleavage site. L. monocytogenes expressing this truncated LLO showed a reduced capacity to disrupt the phagosomal membranes of bone marrow macrophages and of hepatocytes; and the mutant strain showed a 100-fold decrease in virulence in the mouse model. These results suggest that the first N-terminal residues of mature LLO participate directly in phagosomal escape and bacterial infection.


2016 ◽  
Vol 113 (37) ◽  
pp. 10352-10357 ◽  
Author(s):  
Tatjana Braun ◽  
Matthijn R. Vos ◽  
Nir Kalisman ◽  
Nicholas E. Sherman ◽  
Reinhard Rachel ◽  
...  

The bacterial flagellar apparatus, which involves ∼40 different proteins, has been a model system for understanding motility and chemotaxis. The bacterial flagellar filament, largely composed of a single protein, flagellin, has been a model for understanding protein assembly. This system has no homology to the eukaryotic flagellum, in which the filament alone, composed of a microtubule-based axoneme, contains more than 400 different proteins. The archaeal flagellar system is simpler still, in some cases having ∼13 different proteins with a single flagellar filament protein. The archaeal flagellar system has no homology to the bacterial one and must have arisen by convergent evolution. However, it has been understood that the N-terminal domain of the archaeal flagellin is a homolog of the N-terminal domain of bacterial type IV pilin, showing once again how proteins can be repurposed in evolution for different functions. Using cryo-EM, we have been able to generate a nearly complete atomic model for a flagellar-like filament of the archaeon Ignicoccus hospitalis from a reconstruction at ∼4-Å resolution. We can now show that the archaeal flagellar filament contains a β-sandwich, previously seen in the FlaF protein that forms the anchor for the archaeal flagellar filament. In contrast to the bacterial flagellar filament, where the outer globular domains make no contact with each other and are not necessary for either assembly or motility, the archaeal flagellin outer domains make extensive contacts with each other that largely determine the interesting mechanical properties of these filaments, allowing these filaments to flex.


2020 ◽  
Vol 202 (20) ◽  
Author(s):  
Derek R. Lovley ◽  
Dawn E. Holmes

ABSTRACT Electrically conductive protein nanowires appear to be widespread in the microbial world and are a revolutionary “green” material for the fabrication of electronic devices. Electrically conductive pili (e-pili) assembled from type IV pilin monomers have independently evolved multiple times in microbial history as have electrically conductive archaella (e-archaella) assembled from homologous archaellin monomers. A role for e-pili in long-range (micrometer) extracellular electron transport has been demonstrated in some microbes. The surprising finding of e-pili in syntrophic bacteria and the role of e-pili as conduits for direct interspecies electron transfer have necessitated a reassessment of routes for electron flux in important methanogenic environments, such as anaerobic digesters and terrestrial wetlands. Pilin monomers similar to those found in e-pili may also be a major building block of the conductive “cables” that transport electrons over centimeter distances through continuous filaments of cable bacteria consisting of a thousand cells or more. Protein nanowires harvested from microbes have many functional and sustainability advantages over traditional nanowire materials and have already yielded novel electronic devices for sustainable electricity production, neuromorphic memory, and sensing. e-pili can be mass produced with an Escherichia coli chassis, providing a ready source of material for electronics as well as for studies on the basic mechanisms for long-range electron transport along protein nanowires. Continued exploration is required to better understand the electrification of microbial communities with microbial nanowires and to expand the “green toolbox” of sustainable materials for wiring and powering the emerging “Internet of things.”


Microbiology ◽  
2009 ◽  
Vol 155 (12) ◽  
pp. 4005-4013 ◽  
Author(s):  
Ruifu Zhang ◽  
John J. LiPuma ◽  
Carlos F. Gonzalez

Bacterial type IV secretion systems (T4SS) perform two fundamental functions related to pathogenesis: the delivery of effector molecules to eukaryotic target cells, and genetic exchange. Two T4SSs have been identified in Burkholderia cenocepacia K56-2, a representative of the ET12 lineage of the B. cepacia complex (Bcc). The plant tissue watersoaking (Ptw) T4SS encoded on a resident 92 kb plasmid is a chimera composed of VirB/D4 and F-specific subunits, and is responsible for the translocation of effector(s) that have been linked to the Ptw phenotype. The bc-VirB/D4 system located on chromosome II displays homology to the VirB/D4 T4SS of Agrobacterium tumefaciens. In contrast to the Ptw T4SS, the bc-VirB/D4 T4SS was found to be dispensable for Ptw effector(s) secretion, but was found to be involved in plasmid mobilization. The fertility inhibitor Osa did not affect the secretion of Ptw effector(s) via the Ptw system, but did disrupt the mobilization of a RSF1010 derivative plasmid.


1984 ◽  
Vol 98 (5) ◽  
pp. 1637-1644 ◽  
Author(s):  
R Mayne ◽  
H Wiedemann ◽  
M H Irwin ◽  
R D Sanderson ◽  
J M Fitch ◽  
...  

The location of the epitopes for monoclonal antibodies against chicken type IV and type V collagens were directly determined in the electron microscope after rotary shadowing of antibody/collagen mixtures. Three monoclonal antibodies against type IV collagen were examined, each one of which was previously demonstrated to be specific for only one of the three pepsin-resistant fragments of the molecule. The three native fragments were designated (F1)2F2, F3, and 7S, and the antibodies that specifically recognize each fragment were called, respectively, IA8 , IIB12 , and ID2 . By electron microscopy, monoclonal antibody IA8 recognized an epitope located in the center of fragment (F1)2F2 and in tetramers of type IV collagen at a distance of 288 nm from the 7S domain, the region of overlap of four type IV molecules. Monoclonal antibody IIB12 , in contrast, recognized an epitope located only 73 nm from the 7S domain. This result therefore provides direct visual evidence that the F3 fragment is located closest to the 7S domain and the order of the fragments must be 7S-F3-(F1)2F2. The epitope for antibody ID2 was located in the overlap region of the 7S domain, and often several antibody molecules were observed to binding to a single 7S domain. The high frequency with which antibody molecules were observed to bind to fragments of type IV collagen suggests that there is a single population of type IV molecules of chain organization [alpha 1(IV)]2 alpha 2(IV), and that four identical molecules must form a tetramer that is joined in an antiparallel manner at the 7S domain. The monoclonal antibodies against type V collagen, called AB12 and DH2 , were both found to recognize epitopes close to one another, the epitopes being located 45-48 nm from one end of the type V collagen molecule. The significance of this result still remains uncertain, but suggests that this site is probably highly immunoreactive. It may also be related to the specific cleavage site of type V collagen by selected metalloproteinases and by alpha-thrombin. This cleavage site is also known to be located close to one end of the type V molecule.


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