Topology and acylation of spiralin

Wróblewski, Henri; Nyström, Staffan; Blanchard, Alain; Wieslander, Åke

doi:10.1128/jb.171.9.5039-5047.1989

Cited by 40 publications

(32 citation statements)

References 50 publications

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“…We propose a topological model for the arrangement of spiralin or S. melliferum spiralin in the spiroplasmal cell membrane. This model agrees well with immunobiological results on membrane topology of spiralin as recently published (29). …”

supporting

confidence: 81%

“…Disulfide bonds involving cysteine have been implicated in the formation of oligomers (26) 172,1990 on April 3, 2019 by guest http://jb.asm.org/ Downloaded from does not seem to apply to the spiralin of S. melliferum BC3T, which contains only one Cys residue as shown in this work, or to that of strain B88, which lacks cysteine (30). It is also known that the spiralin of S. melliferum B88 can be acylated with palmitic acid through an ester linkage involving the hydroxyl group of Ser or Thr residues (27,29). The precise position of the involved residue in the molecule is, however, unknown.…”

Section: Discussionmentioning

confidence: 80%

“…In this way, the small C-terminal domain remains on the cytoplasmic face of the membrane. Biochemical and immunobiological data suggest a model in which two hydrophilic domains protrude on the two faces of the membrane (21,29).…”

Section: Discussionmentioning

confidence: 99%

“…The covalently bound acyl chain would anchor the a-helix, and hence the whole spiralin molecule, in the lipid bilayer. Strengthening of spiralin anchoring in the spiroplasmal membrane through acylation has been proposed (29).…”

Section: Discussionmentioning

confidence: 99%

“…Only the putative a-helix involving residues 162 to 181 has the size required for membrane spanning (20) and could represent the transmembrane domain of spiralin, which is well known to be an integral membrane protein (25,29). Axial projection of this a-helix (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Spiralins of Spiroplasma citri and Spiroplasma melliferum: amino acid sequences and putative organization in the cell membrane

1990

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Spiralin is the major membrane protein of the helical mollicute Spiroplasma citri. A similar protein occurs in the membrane of Spiroplasma melliferum, an organism related to S. citri. The gene encoding spiralin has been sequenced. A restriction fragment of the spiralin gene has been used as a probe to detect the gene encoding S. melliferum spiralin. A 4.6-kilobase-pair ClaI DNA fragment from S. melliferum strongly hybridized with the probe. This fragment was inserted in pBR322 and cloned in Escherichia coli. It was further subcloned in the replicative forms of M13mpl8 and M13mpl9, and its nucleotide sequence was determined (GenBank accession number M33991). An open reading frame showing 88.6% base sequence homology with the S. citri spiralin gene could be identified and was assumed to be the gene encoding S. melliferum spiralin. The deduced amino acid sequence of the protein had 75% homology with the spiralin sequence. In particular, the two proteins possess a stretch of 20 amino acids which can form an a-helix, in which all polar amino acids occupy approximately one-third of the axial projection down the helix. On the basis of these data and published data, we propose a topological model for the structural organization of the spiralin in the cell membrane of spiroplasmas.The cell membrane of the helical mollicute Spiroplasma citri (17) contains a major protein termed spiralin (28) which represents more than 20% of the total membrane proteins. Spiralin is an integral amphiphilic protein (25). The gene encoding spiralin has been cloned and expressed in Escherichia coli (14), and the spiroplasmal DNA insert of recombinant plasmid pES3' harboring the spiralin gene has been sequenced (5). Among the six open reading frames (ORF) present on the S. citri DNA insert, the ORF corresponding to the spiralin gene was identified by the size and amino acid composition of its sequence-deduced translational product. Spiralin was found to contain 241 amino acids and had a molecular mass of 25,282 daltons (Da) (5). The role of spiralin is not yet known.A major protein has also been found in the cell membrane of Spiroplasma melliferum BC3T (1) and B88 (30). The molecular weights and amino acid compositions of spiralin (the protein from S. citri) and S. melliferum spiralin are similar. However, only weak serological relationships have been observed between the two proteins (8, 23). Proteins similar to spiralin are probably present in spiroplasma species other than S. melliferum and could be characteristic of the spiroplasmas. They may well have structural and functional similarities.We have now cloned and sequenced the gene encoding spiralin of S. melliferum BC3T. We show that spiralin and S. melliferum spiralin have 75% amino acid homology and their predicted secondary structures are similar. We propose a topological model for the arrangement of spiralin or S. melliferum spiralin in the spiroplasmal cell membrane. This model agrees well with immunobiological results on membrane topology of spiralin as recently published (29).

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supporting

confidence: 81%

Section: Discussionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Spiralins of Spiroplasma citri and Spiroplasma melliferum: amino acid sequences and putative organization in the cell membrane

1990

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Spiroplasma

Williamson¹,

Gasparich²,

Regassa³

et al. 2015

Bergey's Manual of Systematics of Archaea and Bacteria

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Spi.ro.plas'ma. Gr. n. speira (L. transliteration spira ) a coil, spiral; Gr. neut. n. plasma something formed or molded, a form; N.L. neut. n. Spiroplasma spiral form. Tenericutes / Mollicutes / Entomoplasmatales / Spiroplasmataceae / Spiroplasma Cells are pleomorphic, varying in size and shape from helical and branched nonhelical filaments to spherical or ovoid. The helical forms, usually 100–200 nm in diameter and 3–5 µm in length, generally occur during the exponential phase of growth and in some species persist during stationary phase. The cells of some species are short (1–2 µm). In certain cases, helical cells may be very tightly coiled, or the coils may show continuous variation in amplitude. Spherical cells ~300 nm in diameter and nonhelical filaments are frequently seen in the stationary phase, where they may not be viable, and in all growth phases in suboptimal growth media, where they may or may not be viable. In some species during certain phases, spherical forms may be the replicating form. Helical filaments are motile, with flexional and twitching movements, and often show an apparent rotatory motility. Fibrils are associated with the membrane, but flagellae, periplasmic fibrils, or other organelles of locomotion are absent . Fimbriae and pili observed on the cell surface of insect‐ and plant‐pathogenic spiroplasmas are believed to be involved in host‐cell attachment and conjugation (Ammar et al., 2004; Özbek et al., 2003), but not in locomotion. Cells divide by binary fission, with doubling times of 0.7–37 h. Facultatively anaerobic. The temperature growth range varies among species, from 5 to 41°C. Colonies on solid media are frequently diffuse , with irregular shapes and borders, a condition that reflects the motility of the cells during active growth (Figure 111). Colony type is strongly dependent on the agar concentration. Colony sizes vary from 0.1 to 4.0 mm in diameter. Colonies formed by nonmotile variants or mutants, or by cultures growing on inadequate media are typically umbonate with diameters of 200 µm or less. Some species, such as Spiroplasma platyhelix , have barely visible helicity along most of their length and display little rotatory or flexing motility. Colonies of motile, fast‐growing spiroplasmas are diffuse, often with satellite colonies developing from foci adjacent to the initial site of colony development. Light turbidity may be produced in liquid cultures. Chemo‐organotrophic. Acid is produced from glucose. Hydrolysis of arginine is variable. Urea, arbutin, and esculin are not hydrolyzed. Sterol requirements are variable. An optimum osmolality, usually in the range of 300–800 mOsm, has been demonstrated for some spiroplasmas. Media containing mycoplasma broth base, serum, and other supplements are required for primary growth, but after adaptation, growth often occurs in less complex media. Defined or semi‐defined media are available for some species. Resistant to 10,000 U/ml penicillin. Insensitive to rifampicin, sensitive to erythromycin and tetracycline. Isolated from the surfaces of flowers and other plant parts, from the guts and hemolymph of various insects and crustaceans, and from tick triturates. Also isolated from vascular plant fluids ( phloem sap ) and insects that feed on the fluids . Specific host associations are common. The type species, Spiroplasma citri , is pathogenic for citrus (e.g., orange and grapefruit), producing “stubborn” disease. Experimental or natural infections also occur in horseradish, periwinkle, radish, broad bean, carrot, and other plant species. Spiroplasma kunkelii is a maize pathogen. Some species are pathogenic for insects. Certain species are pathogenic, under experimental conditions, for a variety of suckling rodents (rats, mice, hamsters and rabbits) and/or chicken embryos. Genome sizes vary from 780 to 2220 kbp (PFGE). DNA G + C content ( mol %): 24–31 ( T m , Bd). Type species : Spiroplasma citri Saglio, L'Hospital, Laflèche, Dupont, Bové, Tully and Freundt 1973, 202 AL .

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Spiroplasma

Gasparich¹,

Kuo²,

Foissac³

2020

Bergey's Manual of Systematics of Archaea and Bacteria

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Spi.ro.plas'ma. Gr. fem. n. speira (L. transliteration spira ) a coil, spiral; Gr. neut. n. plasma something formed or molded, a form; N.L. neut. n. Spiroplasma spiral form. Tenericutes / Mollicutes / Entomoplasmatales / Spiroplasmataceae / Spiroplasma Cells are pleomorphic, varying in size and shape from helical and branched nonhelical filaments to spherical or ovoid. The helical forms, usually 100–200 nm in diameter and 3–5 μm in length, generally occur during the exponential phase of growth and in some species persist during stationary phase. The cells of some species are short (1–2 μm). In certain cases, helical cells may be very tightly coiled, or the coils may show continuous variation in amplitude. Spherical cells ∼300 nm in diameter and nonhelical filaments are frequently seen in the stationary phase, where they may not be viable, and in all growth phases in suboptimal growth media, where they may or may not be viable. In some species during certain phases, spherical forms may be the replicating form. Helical filaments are motile, with flexional and twitching movements, and often show an apparent rotatory motility. Fibrils are associated with the membrane, but flagella, periplasmic fibrils, or other organelles of locomotion are absent . Fimbriae‐like and pili‐like structures observed on the cell surface of insect‐ and plant‐pathogenic spiroplasmas are believed to be involved in host‐cell attachment and conjugation (Ammar et al., 2004; Özbek et al., 2003), but not in locomotion. Cells divide by binary fission, with doubling times of 0.7–37 h. Facultatively anaerobic. The temperature growth range varies among species, from 5 to 41°C. Colonies on solid media are frequently diffuse , with irregular shapes and borders, a condition that reflects the motility of the cells during active growth. Colony type is strongly dependent on the agar concentration. Colony sizes vary from 0.1 to 4.0 mm in diameter. Colonies formed by nonmotile variants or mutants, or by cultures growing on inadequate media are typically umbonate with diameters of 200 μm or less. Some species, such as Spiroplasma platyhelix , have barely visible helicity along most of their length and display little rotatory or flexing motility. Colonies of motile, fast‐growing spiroplasmas are diffuse, often with satellite colonies developing from foci adjacent to the initial site of colony development. Light turbidity may be produced in liquid cultures. Chemo‐organotrophic. Acid is produced from glucose. Hydrolysis of arginine is variable. Urea, arbutin, and esculin are not hydrolyzed. Sterol requirements are variable. An optimum osmolality, usually in the range of 300–800 mOsm, has been demonstrated for some spiroplasmas. Media containing mycoplasma broth base, serum, and other supplements are required for primary growth, but after adaptation, growth often occurs in less complex media. Defined or semi‐defined media are available for some species. Resistant to 10,000 U/ml penicillin. Insensitive to rifampicin, sensitive to erythromycin and tetracycline. Isolated from the surfaces of flowers and other plant parts, from the guts and hemolymph of various insects and crustaceans, and from tick triturates. Also isolated from vascular plant fluids ( phloem sap ) and insects that feed on the fluids . Specific host associations are common. The type species, Spiroplasma citri , is pathogenic for citrus (e.g., orange and grapefruit), producing “stubborn” disease. Experimental or natural infections also occur in horseradish, periwinkle, radish, broad bean, carrot, and other plant species. Spiroplasma kunkelii is a maize pathogen. Some species are pathogenic for insects. Certain species are pathogenic, under experimental conditions, for a variety of suckling rodents (rats, mice, hamsters, and rabbits) and/or chicken embryos. Genome sizes vary from 780 to 2,220 kb (PFGE). DNA G + C content ( mol %): 24–31 ( T m , Bd). Type species : Spiroplasma citri Saglio et al. 1973 AL .

show abstract

Topology and acylation of spiralin

Cited by 40 publications

References 50 publications

Spiralins of Spiroplasma citri and Spiroplasma melliferum: amino acid sequences and putative organization in the cell membrane

Spiralins of Spiroplasma citri and Spiroplasma melliferum: amino acid sequences and putative organization in the cell membrane

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