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Activation pattern and toxicity of the Cry11Bb1 toxin of Bacillus thuringiensis subsp. medellin.
J Invertebr Pathol. 2000 Jul; 76(1):56-62.JI

Abstract

Bacillus thuringiensis protoxins undergo proteolytic processing in the midgut of susceptible insects to become active. The ability to process the Cry11Bb1 protoxin by trypsin and Culex quinquefasciatus larval gut extracts was tested. The protease activity indicated by the appearance of proteolytic products increased with an increment in pH, with the highest activity being observed at pH 10.6. A time course study showed the proteolysis of the 94-kDa Cry11Bb protein ending with the production of fragments of relative molecular mass of 30 and 35 kDa within 5 min. In vitro, gut proteases extract cleaved the solubilized toxin between Ser59 and Ile60 and between Ala395 and Asn396, generating a 30-kDa N-terminal and a 35-kDa C-terminal fragment, respectively. Similarly, mosquito larvae processed in vivo the parasporal inclusions, generating the same fragments as those observed in vitro. The Cry11Bb1 protoxin activated with trypsin or gut proteases showed larvicidal activity against C. quinquefasciatus first instar larvae. The data suggest that gut proteases participate in the activation of CryllBbl protoxin, generating at least two different fragments on which the activity could reside.

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Authors+Show Affiliations

Segura C
Unidad de Biotecnología y Control Biológico, Corporación para Investigaciones Biológicas, Medellin, Colombia.
Guzman F
No affiliation info available
Patarroyo ME
No affiliation info available
Orduz S
No affiliation info available

MeSH

Amino Acid SequenceAnimalsBacillus thuringiensisBacterial ProteinsBacterial ToxinsCulexEndotoxinsHydrogen-Ion ConcentrationMolecular Sequence DataPest Control, BiologicalProtein PrecursorsProtein Processing, Post-TranslationalSequence AnalysisSolubilityTime FactorsTrypsin

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10963404

Citation

Segura, C, et al. "Activation Pattern and Toxicity of the Cry11Bb1 Toxin of Bacillus Thuringiensis Subsp. Medellin." Journal of Invertebrate Pathology, vol. 76, no. 1, 2000, pp. 56-62.
Segura C, Guzman F, Patarroyo ME, et al. Activation pattern and toxicity of the Cry11Bb1 toxin of Bacillus thuringiensis subsp. medellin. J Invertebr Pathol. 2000;76(1):56-62.
Segura, C., Guzman, F., Patarroyo, M. E., & Orduz, S. (2000). Activation pattern and toxicity of the Cry11Bb1 toxin of Bacillus thuringiensis subsp. medellin. Journal of Invertebrate Pathology, 76(1), 56-62.
Segura C, et al. Activation Pattern and Toxicity of the Cry11Bb1 Toxin of Bacillus Thuringiensis Subsp. Medellin. J Invertebr Pathol. 2000;76(1):56-62. PubMed PMID: 10963404.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Activation pattern and toxicity of the Cry11Bb1 toxin of Bacillus thuringiensis subsp. medellin. AU - Segura,C, AU - Guzman,F, AU - Patarroyo,M E, AU - Orduz,S, PY - 2000/8/30/pubmed PY - 2001/2/28/medline PY - 2000/8/30/entrez SP - 56 EP - 62 JF - Journal of invertebrate pathology JO - J Invertebr Pathol VL - 76 IS - 1 N2 - Bacillus thuringiensis protoxins undergo proteolytic processing in the midgut of susceptible insects to become active. The ability to process the Cry11Bb1 protoxin by trypsin and Culex quinquefasciatus larval gut extracts was tested. The protease activity indicated by the appearance of proteolytic products increased with an increment in pH, with the highest activity being observed at pH 10.6. A time course study showed the proteolysis of the 94-kDa Cry11Bb protein ending with the production of fragments of relative molecular mass of 30 and 35 kDa within 5 min. In vitro, gut proteases extract cleaved the solubilized toxin between Ser59 and Ile60 and between Ala395 and Asn396, generating a 30-kDa N-terminal and a 35-kDa C-terminal fragment, respectively. Similarly, mosquito larvae processed in vivo the parasporal inclusions, generating the same fragments as those observed in vitro. The Cry11Bb1 protoxin activated with trypsin or gut proteases showed larvicidal activity against C. quinquefasciatus first instar larvae. The data suggest that gut proteases participate in the activation of CryllBbl protoxin, generating at least two different fragments on which the activity could reside. SN - 0022-2011 UR - https://www.unboundmedicine.com/medline/citation/10963404/Activation_pattern_and_toxicity_of_the_Cry11Bb1_toxin_of_Bacillus_thuringiensis_subsp__medellin_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-2011(00)94945-0 DB - PRIME DP - Unbound Medicine ER -