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Titolo:
Activation and fragmentation of Bacillus thuringiensis delta-endotoxin by high concentrations of proteolytic enzymes
Autore:
Pang, ASD; Gringorten, JL; Bai, C;
Indirizzi:
Canadian Forestry Serv, Great Lakes Forestry Ctr, Sault St Marie, ON P6A 5M7, Canada Canadian Forestry Serv Sault St Marie ON Canada P6A 5M7 N P6A 5M7, Canada
Titolo Testata:
CANADIAN JOURNAL OF MICROBIOLOGY
fascicolo: 10, volume: 45, anno: 1999,
pagine: 816 - 825
SICI:
0008-4166(199910)45:10<816:AAFOBT>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
INSECTICIDAL TOXIN; CRYSTAL PROTEINS; GUT-JUICE; PURIFICATION;
Keywords:
Bacillus thuringiensis endotoxin; Lepidoptera; proteolytic enzymes; insect gut juice; activation; digestion;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Pang, ASD Canadian Forestry Serv, Great Lakes Forestry Ctr, 1219 Queen St E,POB 490,Sault St Marie, ON P6A 5M7, Canada Canadian Forestry Serv 1219 Queen St E,POB 490 Sault St Marie ON Canada P6A 5M7
Citazione:
A.S.D. Pang et al., "Activation and fragmentation of Bacillus thuringiensis delta-endotoxin by high concentrations of proteolytic enzymes", CAN J MICRO, 45(10), 1999, pp. 816-825

Abstract

Commercial enzymes and insect gut juice at various concentrations were used to digest Bacillus thuringiensis subsp. sotto Cry1Aa protoxin and examinethe fragmentation pattern and effect on insecticidal activity. Trypsin at both high (5 mg/mL) and low (0.05 mg/mL) concentrations converted protoxin to toxin with no difference in insecticidal activity against Bombyx mori larvae. In both cases, the toxin protein had an apparent M-r of 58.4 kDa (SDS-PAGE). Active toxin of identical M-r was also produced with low concentrations of Pronase and subtilisin, but at high concentration, it was degraded into two protease-resistant fragments of apparent M-r 31.8 and 29.6 kDa, and exhibited no insecticidal activity. Sequencing data established the primary cleavage site to be in domain II, the receptor-binding region of the toxin, in an exposed loop between two beta-sheet strands. Fragmentation was not observed, however when the digests were analyzed by native protein techniques, but rather the toxin molecule appeared to be intact. The amount of activated toxin produced by Choristoneura fumiferana gut juice was markedly reduced when the gut-juice concentration was increased from 1 to 50% and correlated with a loss in insecticidal activity. However, no lower M-r protease-resistant fragments were evident in the SDS-PAGE of these digests.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 14:21:05