Phospholipase A2 activity of the regularly arranged surface protein of Acinetobacter sp. 199A

Thorne, Kareen J. I.; Oliver, Rhonda C.; Heath, M. F.

doi:10.1016/0005-2760(76)90006-0

Cited by 14 publications

(4 citation statements)

References 16 publications

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“…However, the only evidence regarding its role has been the absolute requirement for virulence (Key et al, 1981;Ishiguro et al, 1981) which appears to be at least partially due to the protection of the cell against serum killing (Munn et al, 1982). It is possible that other mechanisms of virulence attributed to other surface proteins could be ascribed to the A protein such as iron sequestration (Crosa, 1980) or enzymatic activity such as phospholipase A (Thorne et al, 1976). We have so far been unable to demonstrate any ion binding, phospholipase, or protease activity of the A protein, and so in the absence of other evidence the notion persists that the A protein represents a chemical, enzyme, complement, and bacteriophage refractile cell barrier, permeable only to essential solutes.…”

Section: Discussionmentioning

confidence: 99%

Purification and characterization of the cell surface virulent A protein from Aeromonas salmonicida

Phipps¹,

Trust²,

Ishiguro³

et al. 1983

Biochemistry

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The predominant cell surface protein (A protein) of Aeromonas salmonicida has been purified in high yield from outer membranes by using a combination of detergent and chaotropic extraction methods as well as exclusion and ion-exchange chromatography. The A protein was primarily monomeric, Mr 50 000, but readily formed oligomers at high protein or low salt concentrations. Several isoelectric forms were distinguishable with purified protein as well as in situ on the cell surface. Neither phosphate nor carbohydrate was detectable. The A protein was hydrophobic in composition and the N-terminal sequence highly hydrophobic. From CD spectra the A protein exhibited 14% alpha helix and 19-28% beta structure and could also be readily crystallized. By fluorescent antibody staining the A protein was shown to cover the entire cell surface but was absent from A protein deficient mutants. This protein appears to have no apparent enzymatic activity but rather constitutes a macromolecular refractile protein barrier essential for virulence.

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Section: Discussionmentioning

confidence: 99%

Purification and characterization of the cell surface virulent A protein from Aeromonas salmonicida

Phipps¹,

Trust²,

Ishiguro³

et al. 1983

Biochemistry

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“…Indeed, phospholipase A has been identified as a major component of the surface protein coat on the outer membrane of Acinetobacter sp. 199A (Thorne et al, 1976).…”

Section: Discussionmentioning

confidence: 99%

Characteristics of a Lipolytic and Fatty Acid-requiring Butyrivibrio sp. Isolated from the Ovine Rumen

Hazlewood

Dawson

1979

Journal of General Microbiology

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A naturally occurring fatty acid-requiring Butyrivibrio sp. (strain S2), isolated from the ovine rumen, deacylates plant galactolipids, phospholipids and sulpholipids to obtain sufficient fatty acid for growth. Growth in vitro was promoted by adding to the growth medium a single straight-chain saturated fatty acid (C13 to C18) or vaccenic acid. Palmitoleic and oleic acids also supported growth but gave lengthy lag phases probably due to their toxicity. Linolenic and linoleic acids supported good growth but they were completely hydrogenated to trans-11-octadecenoic acid which was incorporated into the bacterial complex lipids. No chain elongation, chain shortening or desaturation of the added fatty acids occurred and all were substantially incorporated into bacterial lipids of the plasmalogen type, partially as a new type of hydrophobic grouping derived from two molecules of fatty acid. The absence of fatty acid unsaturation poses the question of the maintenance of membrane fluidity within this bacterium.

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“…is secreted into the extracellular medium it is possible that the secreted protein has a biological function. The only enzymic activity which has been detected in isolated surface protein is phospholipase A, in Acinetobacter 199A a-protein (Thorne, Oliver & Heath, 1976~). Colonies of Acinetobacter I 99A secrete a phospholipase which produces turbid zones in egg-yolkagar plates.…”

Section: (I) Protectionmentioning

confidence: 99%

Regularly Arranged Protein on the Surfaces of Gram‐negative Bacteria

Thorne

1977

Biological Reviews

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SUMMARY Many species of Gram‐negative bacteria carry a layer of regularly arranged sub‐units on the outer surface of their outer membrane. The subunits are arranged tetra‐gonally or hexagonally and have centre‐to‐centre spacings ranging from 4 to 35 nm, depending on the bacterial species. The regularly arranged layer has been detected by electron microscopy in whole cells, cell walls, outer membranes and assemblies of isolated subunits. The regular arrays can be seen in intact cells by shadowing or freeze‐etching and, occasionally, in thin sections or after negative‐staining. Freeze‐etching and negative‐staining have been used to show the regular arrays in isolated cell walls and outer membranes. Negative‐staining is used in the examination of assembled isolated subunits. Optical diffraction of electron micrographs provides more detailed information of the fine structure of the subunits in the regular array. The regularly arranged surface layer can be removed by protein perturbants, by chelation of divalent cations with EDTA and EGTA, by cation substitution or by acidification. The two surface subunits which have so far been purified have been found to be acidic proteins with molecular weights of 67000 (Acimtobacter 199A) and 140000 (Spirillum serpens). In Acinetobacter 199A the surface protein is attached to the protein of the outer membrane through a salt bridge involving Ca2+ or Mg2+. Evidence exists that there may be a similar mode of attachment in other species. Isolated surface proteins from Acinetobacter 199A and from Spirillum spp. have the ability to reassemble into the same pattern as that seen on the bacterial surface, either in isolation or in the presence of cell‐wall fragments to act as nucleating agents. Self‐assembly of Acinetobacter 199A a‐protein requires chloride ions. Acinetobacter 199A a‐protein can only be incorporated onto the bacterial surface if an intact lipopolysaccharide membrane is formed first to receive the intrinsic membrane proteins to which the a‐protein attaches. Impairment of lipopolysaccharide synthesis by bacitracin prevents incorporation of a‐protein and other membrane proteins into the outer membrane. Continuing incorporation of pre‐formed radioactive a‐protein into the outer membrane in Acimtobacter 199A can be detected for 10 min after transference from radioactive to non‐radioactive growth medium. Spirillum metamorphum, Flexibacter sp. and Acinetobacter 199A synthesize more surface protein than is required to cover the cell surface. The excess is secreted into the growth medium. The regularly arranged surface protein of Acinetobacter 199A provides partial protection against isolated lysosomal proteinases from polymorphonuclear leucocytes. Spirillum spp. is protected from Bdellovibrio invasion by the surface protein. Secreted a‐protein from Acimtobacter 199A has phospholipase A, activity. No phospholipase activity can be detected when the a‐protein is bound to the bacterial surface.

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Phospholipase A2 activity of the regularly arranged surface protein of Acinetobacter sp. 199A

Cited by 14 publications

References 16 publications

Purification and characterization of the cell surface virulent A protein from Aeromonas salmonicida

Purification and characterization of the cell surface virulent A protein from Aeromonas salmonicida

Characteristics of a Lipolytic and Fatty Acid-requiring Butyrivibrio sp. Isolated from the Ovine Rumen

Regularly Arranged Protein on the Surfaces of Gram‐negative Bacteria

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