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In vitro and in vivo proteolysis of the Bacillus thuringiensis subsp. israelensis CryIVD protein by Culex quinquefasciatus larval midgut proteases.
Insect Biochem Mol Biol. 1993 Mar; 23(2):273-83.IB

Abstract

Proteases with trypsin-, chymotrypsin- and thermolysin-like specificity were detected in Culex quinquefasciatus larval midguts. Their activities were monitored by N-terminal amino acid sequence analysis of the Bacillus thuringiensis subsp. israelensis CryIVD toxin proteolytic fragments. These proteases are located in the larval midgut and in different fractions obtained during the preparation of brush border membrane vesicles. The activity of the midgut proteases increased with an increase in pH. Both the chymotrypsin- and thermolysin-like activities are involved in the processing of solubilized CryIVD toxin, whereas an additional trypsin-like protease is necessary for the CryIVD parasporal inclusion processing. The solubilized CryIVD toxin was first cleaved between Thr347 and Phe348 and between Phe348 and Tyr349, generating a 40-kDa N-terminal fragment and a 32.5-kDa C-terminal fragment. The C-terminal domain was resistant to further processing, with only a small amount of a 31-kDa product appearing due to the action of a thermolysin-like protease. However, the N-terminal domain was very unstable, and was further degraded to about 30 kDa. Unlike the solubilized CryIVD toxin, the processing of the CryIVD parasporal inclusion was very slow at neutral pH. Three protease-resistant products were detected at pHs higher than 9.5 with an overnight incubation at 37 degrees C. The 30- and 28.5-kDa C-terminal peptides are proteolytic products of trypsin- and chymotrypsin-like proteases, respectively; while the 28-kDa N-terminal peptide has 27 amino acids deleted from the N-terminal end by a thermolysin-like protease.

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Authors+Show Affiliations

Dai SM
Department of Entomology, University of California, Riverside 92521.
Gill SS
No affiliation info available

MeSH

Amino Acid SequenceAnimalsBacillus thuringiensisBacillus thuringiensis ToxinsBacterial ProteinsBacterial ToxinsBinding SitesCulexDigestive SystemEndopeptidasesEndotoxinsHemolysin ProteinsLarvaMolecular Sequence DataPeptide FragmentsProtein Processing, Post-TranslationalSolubility

Pub Type(s)

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

Language

eng

PubMed ID

8485524

Citation

Dai, S M., and S S. Gill. "In Vitro and in Vivo Proteolysis of the Bacillus Thuringiensis Subsp. Israelensis CryIVD Protein By Culex Quinquefasciatus Larval Midgut Proteases." Insect Biochemistry and Molecular Biology, vol. 23, no. 2, 1993, pp. 273-83.
Dai SM, Gill SS. In vitro and in vivo proteolysis of the Bacillus thuringiensis subsp. israelensis CryIVD protein by Culex quinquefasciatus larval midgut proteases. Insect Biochem Mol Biol. 1993;23(2):273-83.
Dai, S. M., & Gill, S. S. (1993). In vitro and in vivo proteolysis of the Bacillus thuringiensis subsp. israelensis CryIVD protein by Culex quinquefasciatus larval midgut proteases. Insect Biochemistry and Molecular Biology, 23(2), 273-83.
Dai SM, Gill SS. In Vitro and in Vivo Proteolysis of the Bacillus Thuringiensis Subsp. Israelensis CryIVD Protein By Culex Quinquefasciatus Larval Midgut Proteases. Insect Biochem Mol Biol. 1993;23(2):273-83. PubMed PMID: 8485524.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - In vitro and in vivo proteolysis of the Bacillus thuringiensis subsp. israelensis CryIVD protein by Culex quinquefasciatus larval midgut proteases. AU - Dai,S M, AU - Gill,S S, PY - 1993/3/1/pubmed PY - 1993/3/1/medline PY - 1993/3/1/entrez SP - 273 EP - 83 JF - Insect biochemistry and molecular biology JO - Insect Biochem Mol Biol VL - 23 IS - 2 N2 - Proteases with trypsin-, chymotrypsin- and thermolysin-like specificity were detected in Culex quinquefasciatus larval midguts. Their activities were monitored by N-terminal amino acid sequence analysis of the Bacillus thuringiensis subsp. israelensis CryIVD toxin proteolytic fragments. These proteases are located in the larval midgut and in different fractions obtained during the preparation of brush border membrane vesicles. The activity of the midgut proteases increased with an increase in pH. Both the chymotrypsin- and thermolysin-like activities are involved in the processing of solubilized CryIVD toxin, whereas an additional trypsin-like protease is necessary for the CryIVD parasporal inclusion processing. The solubilized CryIVD toxin was first cleaved between Thr347 and Phe348 and between Phe348 and Tyr349, generating a 40-kDa N-terminal fragment and a 32.5-kDa C-terminal fragment. The C-terminal domain was resistant to further processing, with only a small amount of a 31-kDa product appearing due to the action of a thermolysin-like protease. However, the N-terminal domain was very unstable, and was further degraded to about 30 kDa. Unlike the solubilized CryIVD toxin, the processing of the CryIVD parasporal inclusion was very slow at neutral pH. Three protease-resistant products were detected at pHs higher than 9.5 with an overnight incubation at 37 degrees C. The 30- and 28.5-kDa C-terminal peptides are proteolytic products of trypsin- and chymotrypsin-like proteases, respectively; while the 28-kDa N-terminal peptide has 27 amino acids deleted from the N-terminal end by a thermolysin-like protease. SN - 0965-1748 UR - https://www.unboundmedicine.com/medline/citation/8485524/In_vitro_and_in_vivo_proteolysis_of_the_Bacillus_thuringiensis_subsp__israelensis_CryIVD_protein_by_Culex_quinquefasciatus_larval_midgut_proteases_ L2 - https://linkinghub.elsevier.com/retrieve/pii/0965-1748(93)90008-G DB - PRIME DP - Unbound Medicine ER -