scholarly journals Type IV pilin post-translational modifications modulate materials properties of bacterial colonies

2018 ◽  
Author(s):  
R. Zöllner ◽  
T. Cronenberg ◽  
N. Kouzel ◽  
A. Welker ◽  
M. Koomey ◽  
...  
Keyword(s):  
Local Order ◽  
Glycan Structure ◽  
Post Translational Modification ◽  
Extracellular Polymers ◽  
Post Translational Modifications ◽  
Materials Properties ◽  
Type Iv ◽  
Pilin Subunit ◽  
Type Iv Pilin ◽  
Bacterial Type

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.

scholarly journals Single-Residue Changes in the C-Terminal Disulfide-Bonded Loop of the Pseudomonas aeruginosa Type IV Pilin Influence Pilus Assembly and Twitching Motility

2009 ◽  
Vol 191 (21) ◽  
pp. 6513-6524 ◽  
Author(s):  
Hanjeong Harvey ◽  
Marc Habash ◽  
Francisca Aidoo ◽  
Lori L. Burrows
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antigenic Variation ◽  
Intact Protein ◽  
Twitching Motility ◽  
Beta Turn ◽  
Type Iv ◽  
Pilin Subunit ◽  
Type Iv Pilin ◽  
Intersubunit Interactions ◽  
Pilus Assembly

ABSTRACT PilA, the major pilin subunit of Pseudomonas aeruginosa type IV pili (T4P), is a principal structural component. PilA has a conserved C-terminal disulfide-bonded loop (DSL) that has been implicated as the pilus adhesinotope. Structural studies have suggested that DSL is involved in intersubunit interactions within the pilus fiber. PilA mutants with single-residue substitutions, insertions, or deletions in the DSL were tested for pilin stability, pilus assembly, and T4P function. Mutation of either Cys residue of the DSL resulted in pilins that were unable to assemble into fibers. Ala replacements of the intervening residues had a range of effects on assembly or function, as measured by changes in surface pilus expression and twitching motility. Modification of the C-terminal P-X-X-C type II beta-turn motif, which is one of the few highly conserved features in pilins across various species, caused profound defects in assembly and twitching motility. Expression of pilins with suspected assembly defects in a pilA pilT double mutant unable to retract T4P allowed us to verify which subunits were physically unable to assemble. Use of two different PilA antibodies showed that the DSL may be an immunodominant epitope in intact pili compared with pilin monomers. Sequence diversity of the type IVa pilins likely reflects an evolutionary compromise between retention of function and antigenic variation. The consequences of DSL sequence changes should be evaluated in the intact protein since it is technically feasible to generate DSL-mimetic peptides with mutations that will not appear in the natural repertoire due to their deleterious effects on assembly.

scholarly journals The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

2020 ◽  
Vol 295 (19) ◽  
pp. 6594-6604 ◽  
Author(s):  
Devon Sheppard ◽  
Jamie-Lee Berry ◽  
Rémi Denise ◽  
Eduardo P. C. Rocha ◽  
Steve Matthews ◽  
...  
Keyword(s):  
Natural Transformation ◽  
Dna Uptake ◽  
Human Pathogens ◽  
Unusual Structure ◽  
Widespread Distribution ◽  
Solution Structures ◽  
Type Iv ◽  
Filament Assembly ◽  
Pilin Subunit ◽  
Type Iv Pilin

Type IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modeling analyses suggest that the unusual structure of ComGC is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species.

scholarly journals Haloferax volcanii Flagella Are Required for Motility but Are Not Involved in PibD-Dependent Surface Adhesion

2010 ◽  
Vol 192 (12) ◽  
pp. 3093-3102 ◽  
Author(s):  
Manuela Tripepi ◽  
Saheed Imam ◽  
Mechthild Pohlschröder
Keyword(s):  
Critical Role ◽  
Type Iv Pili ◽  
Haloferax Volcanii ◽  
Surface Adhesion ◽  
Functional Roles ◽  
Bacterial Flagella ◽  
Type Iv ◽  
Type Iv Pilin ◽  
Flagellar Assembly ◽  
Bacterial Type

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.

scholarly journals Bacteria defend against phages through type IV pilus glycosylation

2017 ◽  
Author(s):  
Hanjeong Harvey ◽  
Joseph Bondy-Denomy ◽  
Hélène Marquis ◽  
Kristina M. Sztanko ◽  
Alan R. Davidson ◽  
...  
Keyword(s):  
Binding Sites ◽  
Opportunistic Pathogen ◽  
Surface Structures ◽  
Major Type ◽  
Post Translational Modification ◽  
Bacterial Surface ◽  
Specific Phage ◽  
Type Iv ◽  
Type Iv Pilin ◽  
Tail Proteins

ABSTRACTBacterial surface structures such as type IV pili are common receptors for phage. Strains of the opportunistic pathogenPseudomonas aeruginosaexpress one of five different major type IV pilin alleles, two of which are glycosylated with either lipopolysaccharide O-antigen units or polymers of D-arabinofuranose. Here we show that both these post-translational modifications protectP. aeruginosafrom a variety of pilus-specific phages. We identified a phage capable of infecting strains expressing both non-glycosylated and glycosylated pilins, and through construction of a chimeric phage, traced this ability to its unique tail proteins. Alteration of pilin sequence, or masking of binding sites by glycosylation, both block phage infection. The energy invested by prokaryotes in glycosylating thousands of pilin subunits is thus explained by the protection against phage predation provided by these common decorations.SIGNIFICANCEPost-translational modification of bacterial and archaeal surface structures such as pili and flagella is widespread, but the function of these decorations is not clear. We propose that predation by bacteriophages that use these structures as receptors selects for strains that mask potential phage binding sites using glycosylation. Phages are of significant interest as alternative treatments for antibiotic-resistant pathogens, but the ways in which phage interact with host receptors are not well understood. We show that specific phage tail proteins allow for infection of strains with glycosylated pili, providing a foundation for the creation of designer phages that can circumvent first-line bacterial defenses.

scholarly journals Molecular Dissection of Bacterial Nanowires

mBio ◽  
2013 ◽  
Vol 4 (3) ◽  
Author(s):  
Thomas Boesen ◽  
Lars Peter Nielsen
Keyword(s):  
Conclusive Evidence ◽  
Geobacter Sulfurreducens ◽  
Electron Conduction ◽  
Content Type ◽  
Type Iv ◽  
Pilin Subunit ◽  
Type Iv Pilin ◽  
Final Electron ◽  
Conductive Properties ◽  
Final Electron Acceptor

ABSTRACTThe discovery of bacterial conductive structures, termed nanowires, has intrigued scientists for almost a decade. Nanowires enable bacteria to transfer electrons over micrometer distances to extracellular electron acceptors such as insoluble metal oxides or electrodes. Nanowires are pilus based and inGeobacter sulfurreducensare composed of the type IV pilin subunit PilA. Multihemec-type cytochromes have been shown to attach to nanowire pili. Two hypotheses have been proposed for electron conduction in nanowires. The first (termed the metal-like conductivity or MLC hypothesis) claims that the pilus itself has the electron-conductive properties and the attached cytochromes mediate transfer to the final electron acceptor, whereas the second hypothesis (termed the superexchange conductivity or SEC hypothesis) suggests that electrons are “hopping” between heme groups in cytochromes closely aligned with the pilus as a scaffold. In their recent article inmBio, Vargas et al. [M. Vargas, N. S. Malvankar, P.-L. Tremblay, C. Leang, J. A. Smith, P. Patel, O. Snoeyenbos-West, K. P. Nevin, and D. R. Lovley, mBio 4(2):e00210-13, 2013] address this ambiguity through an analysis of strain Aro-5, aG. sulfurreducensPilA mutant lacking aromatic residues in the nonconserved portion of PilA. These residues were suspected of involvement in electron transport according to the MLC hypothesis. TheG. sulfurreducensmutant had reduced conductive properties, lending important support to the MLC hypothesis. The data also highlight the need for further and more conclusive evidence for one or the other hypothesis.

scholarly journals Archaeal flagellin combines a bacterial type IV pilin domain with an Ig-like domain

2016 ◽  
Vol 113 (37) ◽  
pp. 10352-10357 ◽  
Author(s):  
Tatjana Braun ◽  
Matthijn R. Vos ◽  
Nir Kalisman ◽  
Nicholas E. Sherman ◽  
Reinhard Rachel ◽  
...  
Keyword(s):  
Flagellar Apparatus ◽  
Model System ◽  
Terminal Domain ◽  
Type Iv ◽  
Single Protein ◽  
Type Iv Pilin ◽  
Flagellar Filament ◽  
Ignicoccus Hospitalis ◽  
Filament Protein ◽  
Bacterial Type

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.

scholarly journals Type IV Pilin Post-Translational Modifications Modulate Material Properties of Bacterial Colonies

2019 ◽  
Vol 116 (5) ◽  
pp. 938-947 ◽  
Author(s):  
Robert Zöllner ◽  
Tom Cronenberg ◽  
Nadzeya Kouzel ◽  
Anton Welker ◽  
Michael Koomey ◽  
...  
Keyword(s):  
Material Properties ◽  
Post Translational Modifications ◽  
Type Iv ◽  
Type Iv Pilin

scholarly journals The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

2020 ◽  
Author(s):  
Devon Sheppard ◽  
Jamie-Lee Berry ◽  
Rémi Denise ◽  
Eduardo P. C. Rocha ◽  
Steve Matthews ◽  
...  
Keyword(s):  
Natural Transformation ◽  
Homology Modelling ◽  
Dna Uptake ◽  
Human Pathogens ◽  
Unusual Structure ◽  
Solution Structures ◽  
Type Iv ◽  
Filament Assembly ◽  
Pilin Subunit ◽  
Type Iv Pilin

AbstractType IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modelling analyses suggest that ComGC unusual structure is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species.

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
Keyword(s):  
Molecular Analysis ◽  
Cleavage Site ◽  
Signal Sequence ◽  
Sequence Similarity ◽  
Genetic Evidence ◽  
Type Iv ◽  
Type Iv Pilin ◽  
Important Evidence ◽  
Bacterial Type ◽  
Signal Sequence Cleavage Site

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.

Dicarbonyl derived post-translational modifications: chemistry bridging biology and aging-related disease

2020 ◽  
Vol 64 (1) ◽  
pp. 97-110
Author(s):  
Christian Sibbersen ◽  
Mogens Johannsen
Keyword(s):  
Mass Spectrometry ◽  
Future Research ◽  
Amino Acid Residues ◽  
Post Translational Modification ◽  
Dicarbonyl Compounds ◽  
Protein Targets ◽  
Post Translational Modifications ◽  
Reactive Protein ◽  
Glycation End Products ◽  
Direct Mass Spectrometry

Abstract In living systems, nucleophilic amino acid residues are prone to non-enzymatic post-translational modification by electrophiles. α-Dicarbonyl compounds are a special type of electrophiles that can react irreversibly with lysine, arginine, and cysteine residues via complex mechanisms to form post-translational modifications known as advanced glycation end-products (AGEs). Glyoxal, methylglyoxal, and 3-deoxyglucosone are the major endogenous dicarbonyls, with methylglyoxal being the most well-studied. There are several routes that lead to the formation of dicarbonyl compounds, most originating from glucose and glucose metabolism, such as the non-enzymatic decomposition of glycolytic intermediates and fructosyl amines. Although dicarbonyls are removed continuously mainly via the glyoxalase system, several conditions lead to an increase in dicarbonyl concentration and thereby AGE formation. AGEs have been implicated in diabetes and aging-related diseases, and for this reason the elucidation of their structure as well as protein targets is of great interest. Though the dicarbonyls and reactive protein side chains are of relatively simple nature, the structures of the adducts as well as their mechanism of formation are not that trivial. Furthermore, detection of sites of modification can be demanding and current best practices rely on either direct mass spectrometry or various methods of enrichment based on antibodies or click chemistry followed by mass spectrometry. Future research into the structure of these adducts and protein targets of dicarbonyl compounds may improve the understanding of how the mechanisms of diabetes and aging-related physiological damage occur.

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