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Ryan PM, Shaevitz JW, Wolgemuth CW. Bend or Twist? What Plectonemes Reveal about the Mysterious Motility of Spiroplasma. PHYSICAL REVIEW LETTERS 2023; 131:178401. [PMID: 37955476 DOI: 10.1103/physrevlett.131.178401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 09/15/2023] [Indexed: 11/14/2023]
Abstract
Spiroplasma is a unique, helical bacterium that lacks a cell wall and swims using propagating helix hand inversions. These deformations are likely driven by a set of cytoskeletal filaments, but how remains perplexing. Here, we probe the underlying mechanism using a model where either twist or bend drive spiroplasma's chirality inversions. We show that Spiroplasma should wrap into plectonemes at different values of the length and external viscosity, depending on the mechanism. Then, by experimentally measuring the bending modulus of Spiroplasma and if and when plectonemes form, we show that Spiroplasma's helix hand inversions are likely driven by bending.
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Affiliation(s)
- Paul M Ryan
- Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
| | - Joshua W Shaevitz
- Joseph Henry Laboratories of Physics and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
| | - Charles W Wolgemuth
- Department of Physics, University of Arizona, Tucson, Arizona 85721, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA
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2
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Nakane D. Rheotaxis in Mycoplasma gliding. Microbiol Immunol 2023; 67:389-395. [PMID: 37430383 DOI: 10.1111/1348-0421.13090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 07/12/2023]
Abstract
This review describes the upstream-directed movement in the small parasitic bacterium Mycoplasma. Many Mycoplasma species exhibit gliding motility, a form of biological motion over surfaces without the aid of general surface appendages such as flagella. The gliding motility is characterized by a constant unidirectional movement without changes in direction or backward motion. Unlike flagellated bacteria, Mycoplasma lacks the general chemotactic signaling system to control their moving direction. Therefore, the physiological role of directionless travel in Mycoplasma gliding remains unclear. Recently, high-precision measurements under an optical microscope have revealed that three species of Mycoplasma exhibited rheotaxis, that is, the direction of gliding motility is lead upstream by the water flow. This intriguing response appears to be optimized for the flow patterns encountered at host surfaces. This review provides a comprehensive overview of the morphology, behavior, and habitat of Mycoplasma gliding, and discusses the possibility that the rheotaxis is ubiquitous among them.
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Affiliation(s)
- Daisuke Nakane
- Department of Engineering Science, Graduate School of Informatics and Engineering, Tokyo, Japan
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Takahashi D, Miyata M, Fujiwara I. Assembly properties of Spiroplasma MreB involved in swimming motility. J Biol Chem 2023:104793. [PMID: 37150324 DOI: 10.1016/j.jbc.2023.104793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 04/29/2023] [Accepted: 05/02/2023] [Indexed: 05/09/2023] Open
Abstract
Bacterial actin MreB forms filaments formed of antiparallel double strand units. The wall-less helical bacterium Spiroplasma has five MreB homologs (MreB1-5), some of which are involved in an intra-cellular ribbon for driving the bacterium's swimming motility. Although the interaction between MreB units is important for understanding Spiroplasma swimming, the interaction modes of each ribbon component are unclear. Here, we examined the assembly properties of Spiroplasma eriocheiris MreB5 (SpeMreB5), one of the ribbon component proteins that forms sheets. Electron microscopy (EM) revealed that sheet formation was inhibited under acidic conditions and bundle structures were formed under acidic and neutral conditions with low ionic strength. We also used solution assays and identified four properties of SpeMreB5 bundles as follows: (I) bundle formation followed sheet formation; (II) electrostatic interactions were required for bundle formation; (III) the positively charged and unstructured C-terminal region contributed to promoting lateral interactions for bundle formation; and (IV) bundle formation required Mg2+ at neutral pH but was inhibited by divalent cations under acidic pH conditions. During these studies, we also characterized two aggregation modes of SpeMreB5 with distinct responses to ATP. These properties will shed light on SpeMreB5 assembly dynamics at the molecular level.
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Affiliation(s)
- Daichi Takahashi
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan; The OMU Advanced Research Center for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan
| | - Ikuko Fujiwara
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan; The OMU Advanced Research Center for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan; Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan.
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4
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Swimming Motility Assays of Spiroplasma. Methods Mol Biol 2023; 2646:373-381. [PMID: 36842131 DOI: 10.1007/978-1-0716-3060-0_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Spiroplasma swim in liquids without the use of the bacterial flagella. This small helical bacterium propels itself by generating kinks that travel down the cell body. The kink translation is unidirectional, from the leading pole to the lagging pole, during cell swimming in viscous environments. This protocol describes a swimming motility assay of Spiroplasma eriocheiris for visualizing kink translations of the absolute handedness of the body helix with optical microscopy.
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Takahashi D, Miyata M. Sequence analyses of a lipoprotein conserved with bacterial actins responsible for swimming motility of wall-less helical Spiroplasma. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000713. [PMID: 37033705 PMCID: PMC10074174 DOI: 10.17912/micropub.biology.000713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/07/2023] [Accepted: 03/09/2023] [Indexed: 04/11/2023]
Abstract
Spiroplasma is a genus of pathogenic or commensal cell-wall-deficient helical bacterium. Spiroplasma -specific protein fibril and five classes of bacterial actins, MreB1-5, are involved in a helical ribbon structure responsible for helical-cell morphology and swimming motility. A gene for a hypothetical protein-SPE_1229, 7th protein-has been found in the locus coding mreB s. In this study, we characterized the 7th protein using in silico methods and found that it could be a lipoprotein whose gene is encoded downstream of mreB3 and conserved in a clade of Spiroplasma .
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Affiliation(s)
- Daichi Takahashi
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan
- The OMU Advanced Research Center for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan
- Correspondence to: Makoto Miyata (
)
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Kiyama H, Kakizawa S, Sasajima Y, Tahara YO, Miyata M. Reconstitution of a minimal motility system based on Spiroplasma swimming by two bacterial actins in a synthetic minimal bacterium. SCIENCE ADVANCES 2022; 8:eabo7490. [PMID: 36449609 PMCID: PMC9710875 DOI: 10.1126/sciadv.abo7490] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 10/14/2022] [Indexed: 05/24/2023]
Abstract
Motility is one of the most important features of life, but its evolutionary origin remains unknown. In this study, we focused on Spiroplasma, commensal, or parasitic bacteria. They swim by switching the helicity of a ribbon-like cytoskeleton that comprises six proteins, each of which evolved from a nucleosidase and bacterial actin called MreB. We expressed these proteins in a synthetic, nonmotile minimal bacterium, JCVI-syn3B, whose reduced genome was computer-designed and chemically synthesized. The synthetic bacterium exhibited swimming motility with features characteristic of Spiroplasma swimming. Moreover, combinations of Spiroplasma MreB4-MreB5 and MreB1-MreB5 produced a helical cell shape and swimming. These results suggest that the swimming originated from the differentiation and coupling of bacterial actins, and we obtained a minimal system for motility of the synthetic bacterium.
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Affiliation(s)
- Hana Kiyama
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Shigeyuki Kakizawa
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Yuya Sasajima
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
| | - Yuhei O. Tahara
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Graduate School of Science, Osaka Metropolitan University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
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Cytoskeletal components can turn wall-less spherical bacteria into kinking helices. Nat Commun 2022; 13:6930. [PMID: 36376306 PMCID: PMC9663586 DOI: 10.1038/s41467-022-34478-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 10/26/2022] [Indexed: 11/16/2022] Open
Abstract
Bacterial cell shape is generally determined through an interplay between the peptidoglycan cell wall and cytoplasmic filaments made of polymerized MreB. Indeed, some bacteria (e.g., Mycoplasma) that lack both a cell wall and mreB genes consist of non-motile cells that are spherical or pleomorphic. However, other members of the same class Mollicutes (e.g., Spiroplasma, also lacking a cell wall) display a helical cell shape and kink-based motility, which is thought to rely on the presence of five MreB isoforms and a specific fibril protein. Here, we show that heterologous expression of Spiroplasma fibril and MreB proteins confers helical shape and kinking ability to Mycoplasma capricolum cells. Isoform MreB5 is sufficient to confer helicity and kink propagation to mycoplasma cells. Cryoelectron microscopy confirms the association of cytoplasmic MreB filaments with the plasma membrane, suggesting a direct effect on membrane curvature. However, in our experiments, the heterologous expression of MreBs and fibril did not result in efficient motility in culture broth, indicating that additional, unknown Spiroplasma components are required for swimming.
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Takahashi D, Fujiwara I, Sasajima Y, Narita A, Imada K, Miyata M. ATP-dependent polymerization dynamics of bacterial actin proteins involved in Spiroplasma swimming. Open Biol 2022; 12:220083. [PMID: 36285441 PMCID: PMC9597168 DOI: 10.1098/rsob.220083] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
MreB is a bacterial protein belonging to the actin superfamily. This protein polymerizes into an antiparallel double-stranded filament that determines cell shape by maintaining cell wall synthesis. Spiroplasma eriocheiris, a helical wall-less bacterium, has five MreB homologous (SpeMreB1-5) that probably contribute to swimming motility. Here, we investigated the structure, ATPase activity and polymerization dynamics of SpeMreB3 and SpeMreB5. SpeMreB3 polymerized into a double-stranded filament with possible antiparallel polarity, while SpeMreB5 formed sheets which contained the antiparallel filament, upon nucleotide binding. SpeMreB3 showed slow Pi release owing to the lack of an amino acid motif conserved in the catalytic centre of MreB family proteins. Our SpeMreB3 crystal structures and analyses of SpeMreB3 and SpeMreB5 variants showed that the amino acid motif probably plays a role in eliminating a nucleophilic water proton during ATP hydrolysis. Sedimentation assays suggest that SpeMreB3 has a lower polymerization activity than SpeMreB5, though their polymerization dynamics are qualitatively similar to those of other actin superfamily proteins, in which pre-ATP hydrolysis and post-Pi release states are unfavourable for them to remain as filaments.
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Affiliation(s)
- Daichi Takahashi
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan,Graduate School of Science, Osaka City University, Osaka, Japan
| | - Ikuko Fujiwara
- Graduate School of Science, Osaka City University, Osaka, Japan,The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Osaka, Japan,Department of Materials Science and Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Yuya Sasajima
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan,Graduate School of Science, Osaka City University, Osaka, Japan
| | - Akihiro Narita
- Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Katsumi Imada
- Graduate School of Science, Osaka University, Toyonaka, Japan
| | - Makoto Miyata
- Graduate School of Science, Osaka Metropolitan University, Osaka, Japan,The OMU Advanced Research Center for Natural Science and Technology, Osaka Metropolitan University, Osaka, Japan,Graduate School of Science, Osaka City University, Osaka, Japan,The OCU Advanced Research Institute for Natural Science and Technology (OCARINA), Osaka City University, Osaka, Japan
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