MORAXELLA, NEISSERIA, BRANHAMELLA, AND ACINETOBACTER

Henriksen, S. D.

doi:10.1146/annurev.mi.30.100176.000431

Cited by 86 publications

(39 citation statements)

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“…However, apart from the obvious possibility that additional genes may have been disrupted in the mutants, the observed lack of complementation may also be due to lack of expression of the Pseudomonas genes in A. calcoaceticus, since these organisms strongly differ in chromosomal GϩC content (67.2 mol% for P. aeruginosa [51] versus 38 to 45 mol% for Acinetobacter spp. [26]). Moreover, lack of protein export in complementation experiments across species barriers has often proven difficult (69).…”

Section: Discussionmentioning

confidence: 99%

Characterization of lipase-deficient mutants of Acinetobacter calcoaceticus BD413: identification of a periplasmic lipase chaperone essential for the production of extracellular lipase

Kok¹,

Thor²,

Nugteren-Roodzant³

et al. 1995

J Bacteriol

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At the onset of the stationary phase in rich media, the gram-negative soil bacterium Acinetobacter calcoaceticus BD413 produces several lipolytic enzymes (40), which have partly overlapping substrate specificities. BD413 estA, encoding one of the cell-bound esterases (40), and lipA, encoding the extracellular lipase (43), have been cloned and characterized. The regulation of their expression is currently being investigated. In addition, we also aim at defining posttranscriptional factors involved in regulation of enzyme production. The latter aspect is especially important for the extracellular lipase of A. calcoaceticus BD413, since several components involved in export of the protein, including concurrent protein processing events, may have significant control over lipase production.The extracellular lipase of A. calcoaceticus BD413 presumably is exported from the cell via a two-step translocation process (43): across the cytoplasmic membrane, this translocation will be mediated by the Sec system (59, 66), whereas translocation through the outer membrane proceeds via a translocation complex similar to the Xcp system in Pseudomonas spp. (69) and the Pul system in Klebsiella spp. (59). These assumptions are based upon the identification of an N-terminal export signal peptide, indicative of the involvement of a Seclike system, and upon the high degree of similarity of A. calcoaceticus LipA to Pseudomonas lipases that are secreted via a two-step mechanism. Moreover, we have demonstrated that a periplasmic processing enzyme, a protein disulfide oxidoreductase, is required for high-level production of lipase in A. calcoaceticus BD413 (43).In Pseudomonas spp., production of lipases that are similar to Acinetobacter LipA requires the presence of a lipase-specific helper protein, which is N terminally anchored in the cytoplasmic membrane, with its C-terminal domain in the periplasm. Activity of this type of protein is essential for the second lipase translocation step, across the outer membrane (14, 34). In the periplasm, such helper proteins have been shown to mediate the formation of secondary structure elements in the periplasmic form of the lipase, suggesting a chaperone-like function of the helper protein. Unlike the situation in pseudomonads, as yet no essential lipase helper protein has been identified in A. calcoaceticus. In Pseudomonas species, these proteins are invariably encoded downstream of the structural lipase gene, and this is not the case in A. calcoaceticus BD413 (43).Previously, we have reported on the identification of two

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Section: Discussionmentioning

confidence: 99%

Characterization of lipase-deficient mutants of Acinetobacter calcoaceticus BD413: identification of a periplasmic lipase chaperone essential for the production of extracellular lipase

Kok¹,

Thor²,

Nugteren-Roodzant³

et al. 1995

J Bacteriol

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“…Other studies have led to the conclusion that Acinetobacter is a heterogeneous genus. This followed from the observation that the mol% G + C of the bacterial DNA of Acinetobacter strains can vary over a range of 38-47 (Henriksen, 1976). Moreover, it has been found that strains can differ considerably in nutritional properties (Baumann et al, 1968).…”

Section: Discussionmentioning

confidence: 99%

Cell envelope protein profiles of Acinetobacter calcoaceticus strains isolated in hospitals

Dijkshoorn

Michel

Degener

1987

Journal of Medical Microbiology

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“…The ppk gene was found to be 2079 bp in length and to have a GC content of 39 mol %, which is typical of Acinetobacter (Henriksen, 1976). The ppk gene encodes a putative protein of 692 amino acids, compared with 691 in Acinetobacter sp.…”

Section: Sequence Analysis Of the Ppk Genementioning

confidence: 98%

Regulation of polyphosphate kinase gene expression in Acinetobacter baumannii 252

1999

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MORAXELLA, NEISSERIA, BRANHAMELLA, AND ACINETOBACTER

Cited by 86 publications

References 0 publications

Characterization of lipase-deficient mutants of Acinetobacter calcoaceticus BD413: identification of a periplasmic lipase chaperone essential for the production of extracellular lipase

Characterization of lipase-deficient mutants of Acinetobacter calcoaceticus BD413: identification of a periplasmic lipase chaperone essential for the production of extracellular lipase

Cell envelope protein profiles of Acinetobacter calcoaceticus strains isolated in hospitals

Regulation of polyphosphate kinase gene expression in Acinetobacter baumannii 252

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