<i>Bacillus thuringiensis var. morrisoni</i>strain PG14: nucleotide sequence of a gene encoding a 27kDa crystal protein

Earp, David J.

doi:10.1093/nar/15.8.3619

Cited by 37 publications

(20 citation statements)

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“…israelensis (Ward & Ellar, 1984; Waalwijk e t al., 1985) and subsp. morrisoni PG14 (Earp & Ellar, 1987), and CytB from subsp. kyztsbztensis t Present address: MRC Neuroscience Group, Department of Neurobiology, Babraham Institute, Cambridge CB2 4AT, UK.…”

Section: Bacillus Tbtlringiensis (Bt) Is a Gram-positive Bacteriummentioning

confidence: 99%

Biochemical characterization of Bacillus thuringiensis cytolytic -endotoxins

Koni¹,

Ellar

1994

Microbiology

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The entomocidal S-endotoxins CytA and CytB produced by Bacillus thuringiensis (Bt) subspecies israelensis and kyushuensis respectively showed a similar level of toxicity to mosquito larvae but were not toxic to the larvae of the lepidopteran Manduca sexta. CytA and CytB are also similar in sequence, predicted secondary structure and a-helical content, the only obvious difference being a C-terminal fifteen residue 'tail' on CytB. Investigations of the function, if any, of the CytB C-terminal 'tail' showed that this S-endotoxin is highly expressed and forms inclusions in an acrystalliferous Bt mutant without the aid of the 20 kDa 'helper' protein from Bt subspecies israelensis which is essential for CytA inclusion formation. After proteinase K treatment, CytA and CytB were processed to virtually the same points in a sequence alignment and were equally haemolytic in vitro. However, the results suggested that unprocessed CytB differs from unprocessed CytA in that the former is not haemolytic. 1

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Section: Bacillus Tbtlringiensis (Bt) Is a Gram-positive Bacteriummentioning

confidence: 99%

Biochemical characterization of Bacillus thuringiensis cytolytic -endotoxins

Koni¹,

Ellar

1994

Microbiology

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“…Seven cytolytic, mosquitocidal-specific toxins are currently known (Earp & Ellar, 1987;Drobniewski & Ellar, 1989;Yu et al, 1991;Koni & Ellar, 1993;Cheong & Gill, 1997;Guerchicoff et al, 1997;Thiery et al, 1997). Using heavyatom isomorphous replacement, the crystal structure of Cyt2Aa from B. thuringiensis subsp.…”

Section: Introductionmentioning

confidence: 99%

“…The broad cytolytic activity of Cyt1Aa has been attributed to its hydrophobicity and ability to bind zwitterionic phospholipids (Thomas & Ellar, 1983a, b). Cyt1Aa is inserted into the membrane to create cation-selective single channels of 1-2 nm in diameter, leading to colloid-osmotic lysis (Knowles & Ellar, 1987;Knowles et al, 1989), and induces leakage of low-molecular-mass substances from lipid vesicles (Drobniewski & Ellar, 1988.Seven cytolytic, mosquitocidal-specific toxins are currently known (Earp & Ellar, 1987;Drobniewski & Ellar, 1989;Yu et al, 1991;Koni & Ellar, 1993;Cheong & Gill, 1997;Guerchicoff et al, 1997;Thiery et al, 1997). Using heavyatom isomorphous replacement, the crystal structure of Cyt2Aa from B. thuringiensis subsp.…”

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confidence: 99%

Compaction of the Escherichia coli nucleoid caused by Cyt1Aa

et al. 2003

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Compaction of the Escherichia coli nucleoid in the cell's centre was associated with the loss of colony-forming ability; these effects were caused by induction of Cyt1Aa, the cytotoxic 27 kDa protein from Bacillus thuringiensis subsp. israelensis. Cyt1Aa-affected compaction of the nucleoids was delayed but eventually more intense than compaction caused by chloramphenicol. The possibility that small, compact nucleoids in Cyt1Aa-expressing cells resulted in DNA replication run-out and segregation following cell division was ruled out by measuring relative nucleoid length. Treatments with membrane-perforating substances other than Cyt1Aa did not cause such compaction of the nucleoids, but rather the nucleoids overexpanded to occupy nearly all of the cell volume. These findings support the suggestion that, in addition to its perforating ability, Cyt1Aa causes specific disruption of nucleoid associations with the cytoplasmic membrane. In situ immunofluorescence labelling with Alexa did not demonstrate a great amount of Cyt1Aa associated with the membrane. Clear separation between Alexa-labelled Cyt1Aa and 49,6-diamidino-2-phenylindole (DAPI)-stained DNA indicates that the nucleoid does not bind Cyt1Aa. Around 2 h after induction, nucleoids in Cyt1Aa-expressing cells started to decompact and expanded to fill the whole cell volume, most likely due to partial cell lysis without massive peptidoglycan destruction. INTRODUCTIONDuring sporulation, various subspecies of the Grampositive soil bacterium Bacillus thuringiensis produce large amounts of insecticidal crystal proteins (ICP), the so-called d-endotoxins , each toxic against larvae of a different group of insects. The ICP of B. thuringiensis subsp. israelensis is specific against the larvae of mosquitoes and black flies (Goldberg & Margalit, 1977;Margalith & Ben-Dov, 2000), vectors of many human infectious diseases (Service, 1986). The crystal is composed of four major polypeptides, Cry4Aa, Cry4Ba, Cry11Aa and Cyt1Aa (of 125, 135, 68 and 28 kDa, respectively), which are encoded by genes carried on the~130 kDa plasmid nicknamed pBtoxis (Ben-Dov et al., 1999). Cyt1Aa, which is not homologous to any of the known Cry toxins , is the most prominent of the four polypeptides, but it is less specific than Cry4Aa, Cry4Ba and Cry11Aa, haemolytic and cytotoxic in vitro (Thomas & Ellar, 1983b;Drobniewski & Ellar, 1988;Hofte & Whiteley, 1989). The broad cytolytic activity of Cyt1Aa has been attributed to its hydrophobicity and ability to bind zwitterionic phospholipids (Thomas & Ellar, 1983a, b). Cyt1Aa is inserted into the membrane to create cation-selective single channels of 1-2 nm in diameter, leading to colloid-osmotic lysis (Knowles & Ellar, 1987;Knowles et al., 1989), and induces leakage of low-molecular-mass substances from lipid vesicles (Drobniewski & Ellar, 1988.Seven cytolytic, mosquitocidal-specific toxins are currently known (Earp & Ellar, 1987;Drobniewski & Ellar, 1989;Yu et al., 1991;Koni & Ellar, 1993;Cheong & Gill, 1997;Guerchicoff et al., 1997;Thiery et al., 199...

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“…Seven cytolytic, mosquitocidal toxins are currently known and characterized on the biochemical level (7,12,13,19,21,31,42); the most investigated toxin is Cyt1Aa from B. thuringiensis subsp. israelensis.…”

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confidence: 99%

Partial Restoration of Antibacterial Activity of the Protein Encoded by a Cryptic Open Reading Frame ( cyt1Ca ) from Bacillus thuringiensis subsp. israelensis by Site-Directed Mutagenesis

2005

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Insecticidal crystal proteins of. This was attributed to five amino acid differences between the sequences of its N-terminal moiety and Cyt1Aa. The 3 end of cyt1Ca was truncated (removing the ricin-binding domain of Cyt1Ca), and six single bases were appropriately changed by site-directed mutagenesis, sequentially replacing the noncharged amino acids by charged ones, according to Cyt1Aa, to form several versions. Expression of these mutated cyt1Ca versions caused loss of the colony-forming ability of the corresponding E. coli cells to different extents compared with the original gene. In some mutants this antibacterial effect was associated by significant distortion of cell morphology and in others by generation of multiple inclusion bodies spread along the cell envelope. The described deleterious effects of mutated cyt1Ca versions against E. coli may reflect an evolutionary relationship between Cyt1Aa and Cyt1Ca.

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Bacillus thuringiensis var. morrisonistrain PG14: nucleotide sequence of a gene encoding a 27kDa crystal protein

Cited by 37 publications

References 3 publications

Biochemical characterization of Bacillus thuringiensis cytolytic -endotoxins

Biochemical characterization of Bacillus thuringiensis cytolytic -endotoxins

Compaction of the Escherichia coli nucleoid caused by Cyt1Aa

Partial Restoration of Antibacterial Activity of the Protein Encoded by a Cryptic Open Reading Frame ( cyt1Ca ) from Bacillus thuringiensis subsp. israelensis by Site-Directed Mutagenesis

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