Bacillus thuringiensis Cry1Ab mutants affecting oligomer formation are non-toxic to Manduca sexta larvae.

Jiménez-Juárez, Nuria; Muñóz-Garay, Carlos; Gómez, Isabel; Saab‐Rincón, Gloria; Damián-Almazo, Juanita Yazmin; Gill, Sarjeet S.; Soberón, Mário; Bravo, Alejandra

doi:10.1074/jbc.a113.701314

Cited by 8 publications

(10 citation statements)

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“…You are encouraged to use the Version of Record that, when published, will replace this version. The most up-to-date-version is available at https://doi.org/10.1042/BCJ20210137 proteins have shown to impede oligomerization without affecting binding (19,20). Using the Cry1AaR99E mutant in in vitro competition assays, the biphasic effect was not observed (Fig.…”

Section: The Cry1aa Oligomer Binds Specifically To Sf21 Cells Expressing Seabcc2mentioning

confidence: 99%

Hetero-oligomerization of Bacillus thuringiensis Cry1A proteins enhance binding to the ABCC2 transporter of Spodoptera exigua

Pinos

Joya

Herrero

et al. 2021

Biochemical Journal

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The ABC transporters are membrane proteins that can act as putative receptors for Cry proteins from Bacillus thuringiensis (Bt) in the midgut of different insects. For the beet armyworm, Spodoptera exigua, ABCC2 and ABCC3 have been found to interact with Cry1A proteins, the main insecticidal proteins used in Bt-crops, as well as Bt-based pesticides. The ABCC2 has shown to have specific binding towards Cry1Ac and is involved in the toxic process of Cry1A proteins, but the role of this transporter and how it relates with the Cry1A proteins is still unknown. Here, we have characterized the interactions between the SeABCC2 and the main proteins that bind to the receptor. By labelling the Cry1Aa protein, we have found that virtually all of the binding is in an oligomeric state, a conformation that allowed higher levels of specific binding that could not be achieved by the monomeric protein on its own. Furthermore, we have observed that Cry1A proteins can hetero-oligomerize in the presence of the transporter, which is reflected in an increase in binding and toxicity to SeABCC2-expressing cells. This synergism can be one of the reasons why B. thuringiensis co-expresses different Cry1 proteins that can apparently have similar binding preferences. The results from in vitro competition and ex vivo competition showed that Cry1Aa, Cry1Ab and Cry1Ac share functional binding sites. By using Cry1Ab-Cry1Ac chimeras, the presence of domain I from Cry1A proteins was revealed to be critical for oligomer formation.

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Section: The Cry1aa Oligomer Binds Specifically To Sf21 Cells Expressing Seabcc2mentioning

confidence: 99%

Hetero-oligomerization of Bacillus thuringiensis Cry1A proteins enhance binding to the ABCC2 transporter of Spodoptera exigua

Pinos

Joya

Herrero

et al. 2021

Biochemical Journal

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“…Evidence for post-binding specificity determinants is provided by the effect of toxin oligomerization on specificity. Mutant Cry1Ab toxins incapable of oligomerization lost specificity to Manduca sexta (Jiménez-Juárez et al, 2007). Moreover, modified Cry1A toxins that form toxin oligomers in solution overcome dependency of interactions with cadherin for specificity (Porta et al, 2011) and are active against Cry1A-resistant insects .…”

Section: Specificity Level Vii: Post-binding Eventsmentioning

confidence: 99%

Specificity determinants for Cry insecticidal proteins: Insights from their mode of action

Jurat-Fuentes

Crickmore

2017

Journal of Invertebrate Pathology

152

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“…Since these two peptides can release the haemoglobin, they may be either α-helix membrane pore formers or membrane disrupter as detergent-like model. The poreforming peptides or proteins such as, colicin [27][28][29][30] , Cry toxin [31][32][33] , haemolysin E 34 can disturb the transmembrane potential, pH gradient, and osmotic regulation of the cells which eventually leading to cell lysis. In the detergent-like model, protein will aggregate on the membrane until they could disrupt the structure of the lipid.…”

Section: Discussionmentioning

confidence: 99%

Antimicrobial peptides of Lactobacillus salivarius K4 isolated from chicken intestine

Sangtanoo¹,

Choowongkomon²,

Surat³

et al. 2014

ScienceAsia

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Two cationic antimicrobial peptides, salvicin K (sal K) and antimicrobial-like bacteriocin β (alb β) from Lactobacillus salivarius K4 were isolated from chicken intestine. In the active form, each peptide contains 47 amino acids with 2 cysteine residues. The antimicrobial activity showed that sal K could inhibit the food pathogens Enterococcus faecalis JCM 5803, Lb. plantarum ATCC 14917, and Streptococcus sp. TISTR 1030. The alb β showed activity against E. faecalis JCM 5803, Leuconostoc mesenteroides subsp. mesenteroides JCM 6124, Lb. sakei TISTR 890, Lb. plantarum ATCC 14917, and Streptococcus sp. TISTR 1030. A high concentration of these bacteriocins was found to cause hemolysis in rat erythrocytes. Each peptide was predicted to have a mixed secondary structure of α-helix, β-sheet, and random coil structure with one disulphide bond. Two antimicrobial peptides were found to be unstructured in Tris-Cl pH 9. These two peptides adopted an α-helix conformation in 10% SDS micelles (to simulate the bacterial cell wall). In zwitterionic dodecylphosphocholine micelles and liposome, these two peptides adopted a β-sheet structure. The results suggest that the α-helix is an important conformation for these peptides to express their antimicrobial activity.

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Bacillus thuringiensis Cry1Ab mutants affecting oligomer formation are non-toxic to Manduca sexta larvae.

Cited by 8 publications

References 0 publications

Hetero-oligomerization of Bacillus thuringiensis Cry1A proteins enhance binding to the ABCC2 transporter of Spodoptera exigua

Hetero-oligomerization of Bacillus thuringiensis Cry1A proteins enhance binding to the ABCC2 transporter of Spodoptera exigua

Specificity determinants for Cry insecticidal proteins: Insights from their mode of action

Antimicrobial peptides of Lactobacillus salivarius K4 isolated from chicken intestine

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