The Monomeric, Tetrameric, and Fibrillar Organization of Fib: The Dynamic Building Block of the Bacterial Linear Motor of Spiroplasma melliferum BC3

Cohen-Krausz, Sara; Cabahug, Pamela C.; Trachtenberg, Shlomo

doi:10.1016/j.jmb.2011.04.067

Cited by 25 publications

(55 citation statements)

References 53 publications

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“…Here we extend earlier studies on the structure of Spiroplasma , its dynamic cell geometry and its molecular origins [14], [15], [19], to the spatial and compositional organization of the whole cell and its parts. Using scanning transmission electron microscopy (STEM) [16], [29], [30], we determine ( i ) the mass-per-length of whole intact cells, ( ii ) the mass-per-length of isolated cytoskeletons and cytoskeletal fibrils, and ( iii ) the mass-per-area of cytosol-free cells ( i.e., membrane envelopes).…”

Section: Introductionsupporting

confidence: 75%

“…Negative staining, vitrification, freeze-substitution, data collection and analysis were carried out as described in [15], [16], [18], [19] . Electron micrographs were recorded using an FEI Tecnai TF30 TEM, operating at an accelerating voltage of 300 kV, and equipped with a Gatan Ultrascan 2 k×2 k pixel CCD camera.…”

Section: Methodsmentioning

confidence: 99%

“…They are chemotactic [9]–[11], polar, and active swimmers [12], [13]. Their dynamic helicity [12], [14] can be traced at molecular dimensions [15], [16] to a highly ordered linear motor – a flat, monolayered ribbon assembled from parallel fibrils – that is attached to the inner surface of the tubular cell’s only membrane along the shortest helical line [17]–[21]. Tube and motor are mutually coiled into a dynamic helix [14].…”

Section: Introductionmentioning

confidence: 99%

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A Structural Framework for a Near-Minimal Form of Life: Mass and Compositional Analysis of the Helical Mollicute Spiroplasma melliferum BC3

Trachtenberg¹,

Schuck

Phillips

et al. 2014

PLoS ONE

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Spiroplasma melliferum is a wall-less bacterium with dynamic helical geometry. This organism is geometrically well defined and internally well ordered, and has an exceedingly small genome. Individual cells are chemotactic, polar, and swim actively. Their dynamic helicity can be traced at the molecular level to a highly ordered linear motor (composed essentially of the proteins fib and MreB) that is positioned on a defined helical line along the internal face of the cell’s membrane. Using an array of complementary, informationally overlapping approaches, we have taken advantage of this uniquely simple, near-minimal life-form and its helical geometry to analyze the copy numbers of Spiroplasma’s essential parts, as well as to elucidate how these components are spatially organized to subserve the whole living cell. Scanning transmission electron microscopy (STEM) was used to measure the mass-per-length and mass-per-area of whole cells, membrane fractions, intact cytoskeletons and cytoskeletal components. These local data were fit into whole-cell geometric parameters determined by a variety of light microscopy modalities. Hydrodynamic data obtained by analytical ultracentrifugation allowed computation of the hydration state of whole living cells, for which the relative amounts of protein, lipid, carbohydrate, DNA, and RNA were also estimated analytically. Finally, ribosome and RNA content, genome size and gene expression were also estimated (using stereology, spectroscopy and 2D-gel analysis, respectively). Taken together, the results provide a general framework for a minimal inventory and arrangement of the major cellular components needed to support life.

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Section: Introductionsupporting

confidence: 75%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Structural Framework for a Near-Minimal Form of Life: Mass and Compositional Analysis of the Helical Mollicute Spiroplasma melliferum BC3

Trachtenberg¹,

Schuck

Phillips

et al. 2014

PLoS ONE

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“…citri, and S. eriocheiris), all of which swim via similar kink propagations [5,7,8,9,10,11,13,28]. The duplication and deletion of SMreBs in the Apis group may suggest their diverse swimming formats.…”

Section: Development Of Spiroplasma Swimmingmentioning

confidence: 99%

Phylogenetic origin and sequence features of MreB from the wall-less swimming bacteria Spiroplasma

Takahashi

Fujiwara

Miyata

2020

Preprint

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Spiroplasma are bacteria with a helical cell shape and a lack of 17 peptidoglycan. They belong to the phylum Tenericutes that evolved from 18 Firmicutes, which includes the bacterium Bacillus subtilis. Spiroplasma swimming 19 motility is unrelated to widespread bacterial motilities, such as flagellar motility, and 20 is caused by helicity switching with kinks traveling along the helical cell body. The 21 swimming force is likely generated by five classes of bacterial actin homolog 22 MreBs involved in the helical bone structure. We analyzed sequences of 23 Spiroplasma MreBs (SMreBs) to clarify their phylogeny and sequence features. 24 The maximum likelihood method based on around 5,000 MreB sequences showed 25 that the phylogenetic tree was divided into several radiations: MreBs of 26 conventional bacteria, MreBs of candidate phyla radiation, and radiations for 27 Firmicutes MreB isoforms. SMreBs formed a clade adjacent to the radiation of 28 MreBH, an MreB isoform of Firmicutes. Sequence comparisons of SMreBs and 29 Bacillus MreBs were also performed to clarify the features of SMreB. In SMreBs 2 30 and 4, amino acids involved in the interactions for inter-and intra-protofilament 31 were significantly different from those in Bacillus MreBs. Catalytic glutamic acid 32 and threonine were changed to aspartic acid and lysine, respectively, in SMreB3. 33 2 SMreB5 had a significantly longer C-terminal region than the other MreBs, which 34 possibly forms a protein-protein interaction unique to Spiroplasma. A membrane-35 binding region was not identified in most SMreBs 1 and 4, although it is conserved 36 in many walled bacterial MreBs. These features may support the functions 37 responsible for the unique mechanism of Spiroplasma swimming.38 39 IMPORTANCE Spiroplasma, a small bacterial group, is parasitic to plants and 40 arthropods. Spiroplasma species are globally widespread and swim via a "helicity 41 switching" mechanism. This mechanism is caused by fibril, a Spiroplasma-specific 42 protein, and five classes of MreBs, bacterial actin belonging to the same family as 43 major muscle protein. This study clarified the evolutional and structural features of 44 MreBs and provided possible clues to control the industrial damage caused by 45 Spiroplasma and develop manageable nano-devices to mimic helicity switching.46 47 48 50 The phylum Tenericutes consists of bacteria that evolved from the phylum 51 Firmicutes (1, 2). Currently, Tenericutes is comprised only of the class Mollicutes, 52 which includes the genera Spiroplasma and Mycoplasma. Species of these genera 53 are characterized by small genome size, low guanine and cytosine contents, being 54 mostly parasitic or commensal, and absence of peptidoglycan (3). In addition, they 55 cannot equip conventional machineries for bacterial motility, such as flagella or 56type IV pili, due to the lack of a peptidoglycan layer (4). Instead, they have 57 developed three unique motility systems: mobile type gliding, pneumoniae type 58 gliding, and Spiroplasma swimming (...

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“…Further, two additional small GTPases act in concert with the bacteriofilin cytoskeleton to regulate the dynamic polarity properties of the cell upon which directional motility and reversal depend [Bulyha et al, 2013]. A dependency of cell shape and motility on the cytoskeleton is reminiscent of similar evidence for wall-less Mycoplasma and Spiroplasma cells [Calisto et al, 2012; Cohen-Krausz et al, 2011]. …”

Section: Poorly Characterized Types Of Bacterial Motilitymentioning

confidence: 99%

Microcompartments and Protein Machines in Prokaryotes

Saier

2013

Microb Physiol

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The prokaryotic cell was once thought of as a ‘bag of enzymes' with little or no intracellular compartmentalization. In this view, most reactions essential for life occurred as a consequence of random molecular collisions involving substrates, cofactors and cytoplasmic enzymes. Our current conception of a prokaryote is far from this view. We now consider a bacterium or an archaeon as a highly structured, nonrandom collection of functional membrane-embedded and proteinaceous molecular machines, each of which serves a specialized function. In this article we shall present an overview of such microcompartments including (1) the bacterial cytoskeleton and the apparati allowing DNA segregation during cell division; (2) energy transduction apparati involving light-driven proton pumping and ion gradient-driven ATP synthesis; (3) prokaryotic motility and taxis machines that mediate cell movements in response to gradients of chemicals and physical forces; (4) machines of protein folding, secretion and degradation; (5) metabolosomes carrying out specific chemical reactions; (6) 24-hour clocks allowing bacteria to coordinate their metabolic activities with the daily solar cycle, and (7) proteinaceous membrane compartmentalized structures such as sulfur granules and gas vacuoles. Membrane-bound prokaryotic organelles were considered in a recent Journal of Molecular Microbiology and Biotechnology written symposium concerned with membranous compartmentalization in bacteria [J Mol Microbiol Biotechnol 2013;23:1-192]. By contrast, in this symposium, we focus on proteinaceous microcompartments. These two symposia, taken together, provide the interested reader with an objective view of the remarkable complexity of what was once thought of as a simple noncompartmentalized cell.

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The Monomeric, Tetrameric, and Fibrillar Organization of Fib: The Dynamic Building Block of the Bacterial Linear Motor of Spiroplasma melliferum BC3

Cited by 25 publications

References 53 publications

A Structural Framework for a Near-Minimal Form of Life: Mass and Compositional Analysis of the Helical Mollicute Spiroplasma melliferum BC3

A Structural Framework for a Near-Minimal Form of Life: Mass and Compositional Analysis of the Helical Mollicute Spiroplasma melliferum BC3

Phylogenetic origin and sequence features of MreB from the wall-less swimming bacteria Spiroplasma

Microcompartments and Protein Machines in Prokaryotes

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