f Biochemical characterization of Bacillus thuringiensis cytolytic δ-endotoxins
- Authors: Pandelakis A. Koni†, David J. Ellar
- Author for correspondence: David J. Ellar. Tel: +44 223 333651. Fax: +44 223 333345. e-mail: DJE1@MOLE.BIO.CAM.AC.UK
- First Published Online: 01 August 1994, Microbiology 140: 1869-1880, doi: 10.1099/13500872-140-8-1869
- Subject: Biochemistry
- Issue Published:
The entomocidal δ-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 α-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 δ-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.
Present address: MRC Neuroscience Group, Department of Neurobiology, Babraham Institute, Cambridge CB2 4AT, UK.
The EMBL accession number for the amino acid sequence reported in this Paper is Z14147.
© Society for General Microbiology, 1994 | Published by the Microbiology Society
Article metrics loading...
Full text loading...
Author and Article Information
/content/journal/micro/10.1099/13500872-140-8-1869dcterms_title,dcterms_subject,pub_serialTitlepub_serialIdent:journal/micro AND -contentType:BlogPost104
/content/journal/micro/10.1099/13500872-140-8-1869dcterms_title,dcterms_subject-pub_serialIdent:journal/micro AND -contentType:BlogPost104
Figure data loading....