Assembly and function of the archaeal flagellum

Motility is a common behaviour in prokaryotes. Both bacteria and archaea use flagella for swimming motility, but it has been well documented that structures of the flagellum from these two domains of life are completely different, although they contribute to a similar function. Interestingly, information available to date has revealed that structurally archaeal flagella are more similar to bacterial type IV pili rather than to bacterial flagella. With the increasing genome sequence information and advancement in genetic tools for archaea, identification of the components involved in the assembly of the archaeal flagellum is possible. A subset of these components shows similarities to components from type IV pilus-assembly systems. Whereas the molecular players involved in assembly of the archaeal flagellum are being identified, the mechanics and dynamics of the assembly of the archaeal flagellum have yet to be established. Recent computational analysis in our laboratory has identified conserved highly charged loop regions within one of the core proteins of the flagellum, the membrane integral protein FlaJ, and predicted that these are involved in the interaction with the assembly ATPase FlaI. Interestingly, considerable variation was found among the loops of FlaJ from the two major subkingdoms of archaea, the Euryarchaeota and the Crenarchaeota. Understanding the assembly pathway and creating an interaction map of the molecular players in the archaeal flagellum will shed light on the details of the assembly and also the evolutionary relationship to the bacterial type IV pili-assembly systems.

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Archaeal flagellar ATPase motor shows ATP-dependent hexameric assembly and activity stimulation by specific lipid binding

Biochemical Journal ◽

10.1042/bj20110410 ◽

2011 ◽

Vol 437 (1) ◽

pp. 43-52 ◽

Cited By ~ 44

Author(s):

Abhrajyoti Ghosh ◽

Sophia Hartung ◽

Chris van der Does ◽

John A. Tainer ◽

Sonja-Verena Albers

Keyword(s):

Atp Hydrolysis ◽

Gel Filtration ◽

Lipid Binding ◽

Type Iv Pili ◽

Assembly Systems ◽

Bacterial Flagella ◽

Type Iv ◽

Biochemical Analyses ◽

Archaeal Flagellum ◽

Flagella Assembly

Microbial motility frequently depends on flagella or type IV pili. Using recently developed archaeal genetic tools, archaeal flagella and its assembly machinery have been identified. Archaeal flagella are functionally similar to bacterial flagella and their assembly systems are homologous with type IV pili assembly systems of Gram-negative bacteria. Therefore elucidating their biochemistry may result in insights in both archaea and bacteria. FlaI, a critical cytoplasmic component of the archaeal flagella assembly system in Sulfolobus acidocaldarius, is a member of the type II/IV secretion system ATPase superfamily, and is proposed to be bi-functional in driving flagella assembly and movement. In the present study we show that purified FlaI is a Mn2+-dependent ATPase that binds MANT-ATP [2′-/3′-O-(N′- methylanthraniloyl)adenosine-5′-O-triphosphate] with a high affinity and hydrolyses ATP in a co-operative manner. FlaI has an optimum pH and temperature of 6.5 and 75 °C for ATP hydrolysis. Remarkably, archaeal, but not bacterial, lipids stimulated the ATPase activity of FlaI 3–4-fold. Analytical gel filtration indicated that FlaI undergoes nucleotide-dependent oligomerization. Furthermore, SAXS (small-angle X-ray scattering) analysis revealed an ATP-dependent hexamerization of FlaI in solution. The results of the present study report the first detailed biochemical analyses of the motor protein of an archaeal flagellum.

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

Journal of Bacteriology ◽

10.1128/jb.00133-10 ◽

2010 ◽

Vol 192 (12) ◽

pp. 3093-3102 ◽

Cited By ~ 84

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.

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Dynamic Regulation of Bacterial Type IV Pili in Response to Light Signal

Seibutsu Butsuri ◽

10.2142/biophys.58.207 ◽

2018 ◽

Vol 58 (4) ◽

pp. 207-208

Author(s):

Daisuke NAKANE ◽

Takayuki NISHIZAKA

Keyword(s):

Light Signal ◽

Type Iv Pili ◽

Dynamic Regulation ◽

Type Iv ◽

Bacterial Type

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A comprehensive history of motility and Archaellation in Archaea

FEMS Microbes ◽

10.1093/femsmc/xtab002 ◽

2021 ◽

Author(s):

Ken F Jarrell ◽

Sonja-Verena Albers ◽

J Nuno de Sousa Machado

Keyword(s):

Posttranslational Modifications ◽

State Of The Art ◽

Halophilic Archaea ◽

Biotechnological Potential ◽

Type Iv ◽

Domains Of Life ◽

History Of ◽

Archaeal Flagellum ◽

Comprehensive History ◽

Made In

Abstract Each of the three Domains of life, Eukarya, Bacteria and Archaea, have swimming structures that were all originally called flagella, despite the fact that none were evolutionarily related to either of the other two. Surprisingly, this was true even in the two prokaryotic Domains of Bacteria and Archaea. Beginning in the 1980s, evidence gradually accumulated that convincingly demonstrated that the motility organelle in Archaea was unrelated to that found in Bacteria, but surprisingly shared significant similarities to type IV pili. This information culminated in the proposal, in 2012, that the ‘archaeal flagellum’ be assigned a new name, the archaellum. In this review, we provide a historical overview on archaella and motility research in Archaea, beginning with the first simple observations of motile extreme halophilic archaea a century ago up to state-of-the-art cryo-tomography of the archaellum motor complex and filament observed today. In addition to structural and biochemical data which revealed the archaellum to be a type IV pilus-like structure repurposed as a rotating nanomachine (Beeby et al. 2020), we also review the initial discoveries and subsequent advances using a wide variety of approaches to reveal: complex regulatory events that lead to the assembly of the archaellum filaments (archaellation); the roles of the various archaellum proteins; key posttranslational modifications of the archaellum structural subunits; evolutionary relationships; functions of archaella other than motility and the biotechnological potential of this fascinating structure. The progress made in understanding the structure and assembly of the archaellum is highlighted by comparing early models to what is known today.

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