Regulation of glutamine synthetase.  XII.  Electron microscopy of the enzyme from Escherichia coli

Valentine, R. C.; Shapiro, Bennett M.; Stadtman, Earl R.

doi:10.1021/bi00846a017

Cited by 824 publications

(363 citation statements)

References 8 publications

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“…Ultrathin sectioning and contrasting with lead-citrate solution was performed as described previously (Venable & Coggeshall, 1965). Negative staining was performed according to Valentine et al (1968).…”

Section: Methodsmentioning

confidence: 99%

Anaerobranca gottschalkii sp. nov., a novel thermoalkaliphilic bacterium that grows anaerobically at high pH and temperature.

Prowe¹,

Antranikian²

2001

International Journal of Systematic and Evolutionary Microbiology

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A novel thermoalkaliphilic, obligately anaerobic bacterium was isolated from a humid soil sample of a hot inlet of Lake Bogoria, Kenya. The newly isolated strain grows optimally at pH 9 5 and 50-55 SC and its growth range is pH 6 0-10 5 and 30-65 SC. Unlike the already known thermoalkaliphiles, the strain grows heterotrophically on a variety of mono-and polysaccharides (glucose, ribose, mannose, fructose, sucrose, maltose, starch, pullulan, xylan and cellulose) and on proteinaceous substrates such as yeast extract, peptone and tryptone. No dissimilatory sulfate reduction was observed, whereas thiosulfate was found to enhance growth when glucose or starch were used as substrates. Under optimal conditions, the doubling time is 48 min. Sodium ions are necessary for growth, with an optimal concentration of 230 mM (1 % NaCl, w/v) at pH 9 5. The rod-shaped cells are motile in the exponential growth phase under optimal growth conditions. Despite the Gram-negative staining and negative KOH assay, the strain is a Gram-positive organism, having an atypically thin cell wall. A sheath-like structure occurs at the cell separation area and parts of a surface layer-like structure were also observed. Based on physiological properties and molecular biological analysis, the strain falls within the radiation of the clostridia and represents a new species of Anaerobranca within the Clostridium/Bacillus subphylum of the Gram-positive bacteria. Strain LBS3 T (l DSM 13577 T ) is named Anaerobranca gottschalkii sp. nov. and is designated as the type strain.

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Section: Methodsmentioning

confidence: 99%

Anaerobranca gottschalkii sp. nov., a novel thermoalkaliphilic bacterium that grows anaerobically at high pH and temperature.

Prowe¹,

Antranikian²

2001

International Journal of Systematic and Evolutionary Microbiology

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“…Specimens were prepared for electron microscopy according to the method of Valentine. 21 Briefly, a 50 to 100 lL drop of sample was placed on parafilm, and carbon on mica was floated onto the surface of the drop for 60 s to allow the protein complexes to adhere. The carbon was subsequently floated onto a 100 lL drop of 2% (w/v) aqueous uranyl acetate for 15 s and finally picked up with a 400 mesh copper grid and blotted dry.…”

Section: Electron Microscopymentioning

confidence: 99%

The lambda spanin components Rz and Rz1 undergo tertiary and quaternary rearrangements upon complex formation

et al. 2010

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Phage holins and endolysins have long been known to play key roles in lysis of the host cell, disrupting the cytoplasmic membrane and peptidoglycan (PG) layer, respectively. For phages of Gram-negative hosts, a third class of proteins, the spanins, are involved in disrupting the outer membrane (OM). Rz and Rz1, the components of the lambda spanin, are, respectively, a class II inner membrane protein and an OM lipoprotein, are thought to span the entire periplasm by virtue of C-terminal interactions of their soluble domains. Here, the periplasmic domains of Rz and Rz1 have been purified and shown to form dimeric and monomeric species, respectively, in solution. Circular dichroism analysis indicates that Rz has significant alpha-helical character, but much less than predicted, whereas Rz1, which is 25% proline, is unstructured. Mixture of the two proteins leads to complex formation and an increase in secondary structure, especially alpha-helical content. Moreover, transmission electron-microscopy reveals that Rz-Rz1 complexes form large rod-shaped structures which, although heterogeneous, exhibit periodicities that may reflect coiledcoil bundling as well as a long dimension that matches the width of the periplasm. A model is proposed suggesting that the formation of such bundles depends on the removal of the PG and underlies the Rz-Rz1 dependent disruption of the OM.

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“…The method of VALENTINE et al (23) was employed to examine molecules of acetyl CoA carboxylase in the electron microscope. The purified enzyme was adsorbed on carbon films prepared on cleaved mica and negatively stained with sodium silicotungstate (5% w/v) at pH 7.0 for 2-4 rain at room temperature.…”

Section: Electron Microscopymentioning

confidence: 99%

“…The stain penetrates into three cavities of the molecules which have an average diameter og 50-60 A. In cases where the protein material was recognizable between two adjacent cavities, it measured approximate- A carbon film freshly stripped from mica was floated on a solution of protein (50rtg/ml) as described by VALENTINE et aL (23). The molecules adsorbed on the film were negatively stained in 5% (w/v) sodium silicotungstate pH 7.0 for 4 min.…”

Section: Log Molecular Weightmentioning

confidence: 99%

Properties and morphology of barley embryo acetyl CoA carboxylase

Brock

Kannangara

1976

Carlsberg Res. Commun.

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Acetyl CoA carboxylase was isolated and purified from barley embryos. The purified enzyme fixed CO2 at the rate of 7 to 7.4 lamoles per min per mg protein. It had a molecular weight of 610 000 daltons and one mole of biotin per mole of enzyme. The purified enzyme aggregates during sepharose 6 B gel filtration. Aggregation of the enzyme can be prevented by using i% sodium chloride in the elution buffer. The biotin carboxyl carrier protein of the enzyme was identified as a small polypeptide with a molecular weight of 21 000 daltons. This peptide behaves identically to barley chloroplast biotin carboxyl carrier protein during polyacrylamide disc electrophoresis in phenol: acetic acid: urea. The morphology of purified acetyl CoA carboxylase was studied by electron microscopy using a negative staining technique. This enzyme is a globular protein with a size of 275 + 8 A x 192 + 42 A and displays characteristic cavities.

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Regulation of glutamine synthetase. XII. Electron microscopy of the enzyme from Escherichia coli

Cited by 824 publications

References 8 publications

Anaerobranca gottschalkii sp. nov., a novel thermoalkaliphilic bacterium that grows anaerobically at high pH and temperature.

Anaerobranca gottschalkii sp. nov., a novel thermoalkaliphilic bacterium that grows anaerobically at high pH and temperature.

The lambda spanin components Rz and Rz1 undergo tertiary and quaternary rearrangements upon complex formation

Properties and morphology of barley embryo acetyl CoA carboxylase

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