scholarly journals Bacillus thuringiensis Cyt2Aa2 toxin disrupts cell membranes by forming large protein aggregates

2016 ◽  
Vol 36 (5) ◽  
Author(s):  
Sudarat Tharad ◽  
José L. Toca-Herrera ◽  
Boonhiang Promdonkoy ◽  
Chartchai Krittanai
Keyword(s):  
Bacillus Thuringiensis ◽  
Cell Membranes ◽  
Lipid Membrane ◽  
Membrane Integrity ◽  
Protein Aggregates ◽  
Membrane Disruption ◽  
Large Protein

We show that the lipid membrane disruption by Bacillus thuringiensis (Bt) Cyt2Aa2 is different from the general pore-forming model. Cyt2Aa2 forms protein aggregates that disrupt the lipid membrane integrity.

scholarly journals Nanoprobes to interrogate nonspecific interactions in lipid bilayers: from defect-mediated adhesion to membrane disruption

2021 ◽  
Author(s):  
Giancarlo Rizza ◽  
Nicolò Razza ◽  
Alessio Lavino ◽  
Giulia Fadda ◽  
Lairez Didier ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membrane ◽  
Membrane Integrity ◽  
Membrane Disruption ◽  
Nonspecific Interactions

When a lipid membrane approaches a material/nanomaterial, nonspecific adhesion may occur. The interactions responsible for nonspecific adhesions can either preserve the membrane integrity or lead to its disruption. Despite the...

scholarly journals Intracellular and Extracellular Expression of Bacillus thuringiensis Crystal Protein Cry5B in Lactococcus lactis for Use as an Anthelminthic

2015 ◽  
Vol 82 (4) ◽  
pp. 1286-1294 ◽  
Author(s):  
Evelyn Durmaz ◽  
Yan Hu ◽  
Raffi V. Aroian ◽  
Todd R. Klaenhammer
Keyword(s):  
Bacillus Thuringiensis ◽  
Lactococcus Lactis ◽  
Copy Number ◽  
Oral Delivery ◽  
Membrane Integrity ◽  
Biologically Active ◽  
High Copy Number ◽  
Cry Protein ◽  
Western Blots ◽  
Content Type

ABSTRACTTheBacillus thuringiensiscrystal (Cry) protein Cry5B (140 kDa) and a truncated version of the protein, tCry5B (79 kDa), are lethal to nematodes. Genes encoding the two proteins were separately cloned into a high-copy-number vector with a strong constitutive promoter (pTRK593) inLactococcus lactisfor potential oral delivery against parasitic nematode infections. Western blots using a Cry5B-specific antibody revealed that constitutively expressed Cry5B and tCry5B were present in both cells and supernatants. To increase production,cry5Bwas cloned into the high-copy-number plasmid pMSP3535H3, carrying a nisin-inducible promoter. Immunoblotting revealed that 3 h after nisin induction, intracellular Cry5B was strongly induced at 200 ng/ml nisin, without adversely affecting cell viability or cell membrane integrity. Both Cry5B genes were also cloned into plasmid pTRK1061, carrying a promoter and encoding a transcriptional activator that invoke low-level expression of prophage holin and lysin genes inLactococcuslysogens, resulting in a leaky phenotype. Cry5B and tCry5B were actively expressed in the lysogenic strainL. lactisKP1 and released into cell supernatants without affecting culture growth. Lactate dehydrogenase (LDH) assays indicated that Cry5B, but not LDH, leaked from the bacteria. Lastly, using intracellular lysates fromL. lactiscultures expressing both Cry5B and tCry5B,in vivochallenges ofCaenorhabditis elegansworms demonstrated that the Cry proteins were biologically active. Taken together, these results indicate that active Cry5B proteins can be expressed intracellularly in and released extracellularly fromL. lactis, showing potential for future use as an anthelminthic that could be delivered orally in a food-grade microbe.

scholarly journals Anomalous Pressure Dissociation of Large Protein Aggregates

1989 ◽  
Vol 264 (27) ◽  
pp. 15863-15868
Author(s):  
J L Silva ◽  
M Villas-Boas ◽  
C F S Bonafe ◽  
N C Meirelles
Keyword(s):  
Protein Aggregates ◽  
Large Protein

scholarly journals The interplay between lipids and dopamine on α-synuclein oligomerization and membrane binding

2013 ◽  
Vol 33 (5) ◽  
Author(s):  
Chi L. L. Pham ◽  
Roberto Cappai
Keyword(s):  
Lipid Membranes ◽  
Amyloid Fibrils ◽  
Lipid Membrane ◽  
Hydrophobic Interactions ◽  
Membrane Integrity ◽  
Lipid Vesicles ◽  
Helical Conformation ◽  
Unfolded Protein ◽  
Natively Unfolded Protein ◽  
Natively Unfolded

The deposition of α-syn (α-synuclein) as amyloid fibrils and the selective loss of DA (dopamine) containing neurons in the substantia nigra are two key features of PD (Parkinson's disease). α-syn is a natively unfolded protein and adopts an α-helical conformation upon binding to lipid membrane. Oligomeric species of α-syn have been proposed to be the pathogenic species associated with PD because they can bind lipid membranes and disrupt membrane integrity. DA is readily oxidized to generate reactive intermediates and ROS (reactive oxygen species) and in the presence of DA, α-syn form of SDS-resistant soluble oligomers. It is postulated that the formation of the α-syn:DA oligomers involves the cross-linking of DA-melanin with α-syn, via covalent linkage, hydrogen and hydrophobic interactions. We investigate the effect of lipids on DA-induced α-syn oligomerization and studied the ability of α-syn:DA oligomers to interact with lipids vesicles. Our results show that the interaction of α-syn with lipids inhibits the formation of DA-induced α-syn oligomers. Moreover, the α-syn:DA oligomer cannot interact with lipid vesicles or cause membrane permeability. Thus, the formation of α-syn:DA oligomers may alter the actions of α-syn which require membrane association, leading to disruption of its normal cellular function.

Essential role of amino acids in αD–β4 loop of a Bacillus thuringiensis Cyt2Aa2 toxin in binding and complex formation on lipid membrane

Toxicon ◽  
2013 ◽  
Vol 74 ◽  
pp. 130-137 ◽  
Author(s):  
Kunat Suktham ◽  
Wanwarang Pathaichindachote ◽  
Boonhiang Promdonkoy ◽  
Chartchai Krittanai
Keyword(s):  
Amino Acids ◽  
Bacillus Thuringiensis ◽  
Complex Formation ◽  
Essential Role ◽  
Lipid Membrane

scholarly journals Quantification of C60-induced membrane disruption using a quartz crystal microbalance

RSC Advances ◽  
2018 ◽  
Vol 8 (18) ◽  
pp. 9841-9849 ◽  
Author(s):  
Yuxuan Zeng ◽  
Qi Wang ◽  
Qiu Zhang ◽  
Wei Jiang
Keyword(s):  
Quartz Crystal Microbalance ◽  
Quartz Crystal ◽  
Lipid Membrane ◽  
Electrostatic Force ◽  
Membrane Disruption ◽  
Induced Membrane

Fullerene C60 NPs adhere on lipid membrane due to electrostatic force and cause membrane disruption.

scholarly journals Keeping α-Synuclein at Bay: A More Active Role of Molecular Chaperones in Preventing Mitochondrial Interactions and Transition to Pathological States?

Life ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 289
Author(s):  
Emelie E. Aspholm ◽  
Irena Matečko-Burmann ◽  
Björn M. Burmann
Keyword(s):  
Molecular Chaperones ◽  
Mitochondrial Membrane ◽  
Structural Transition ◽  
Current Knowledge ◽  
Lewy Bodies ◽  
Protein Aggregates ◽  
Active Role ◽  
Proteolytic Processing ◽  
Membrane Disruption

The property of molecular chaperones to dissolve protein aggregates of Parkinson-related α-synuclein has been known for some time. Recent findings point to an even more active role of molecular chaperones preventing the transformation of α-synuclein into pathological states subsequently leading to the formation of Lewy bodies, intracellular inclusions containing protein aggregates as well as broken organelles found in the brains of Parkinson’s patients. In parallel, a short motif around Tyr39 was identified as being crucial for the aggregation of α-synuclein. Interestingly, this region is also one of the main segments in contact with a diverse pool of molecular chaperones. Further, it could be shown that the inhibition of the chaperone:α-synuclein interaction leads to a binding of α-synuclein to mitochondria, which could also be shown to lead to mitochondrial membrane disruption as well as the possible proteolytic processing of α-synuclein by mitochondrial proteases. Here, we will review the current knowledge on the role of molecular chaperones in the regulation of physiological functions as well as the direct consequences of impairing these interactions—i.e., leading to enhanced mitochondrial interaction and consequential mitochondrial breakage, which might mark the initial stages of the structural transition of α-synuclein towards its pathological states.

Analysis of the soybean metallothionein system under free radical stress: protein modification connected to lipid membrane damage

Metallomics ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1792-1804 ◽  
Author(s):  
Mireia Tomàs Giner ◽  
Elena Jiménez-Martí ◽  
Roger Bofill Arasa ◽  
Anna Tinti ◽  
Michele Di Foggia ◽  
...  
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Protein Modification ◽  
Cell Membranes ◽  
Lipid Membrane ◽  
Metal Clusters ◽  
Membrane Damage ◽  
Stress Protein ◽  
Structural Rearrangement ◽  
Free Radical Stress

Metal clusters act as good interceptors of free radicals for four plant metallothioneins: partial deconstruction, structural rearrangement and damage transfer to cell membranes.

scholarly journals Rearrangement of N-Terminal α-Helices of Bacillus thuringiensis Cry1Ab Toxin Essential for Oligomer Assembly and Toxicity

Toxins ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 647
Author(s):  
Sabino Pacheco ◽  
Jean Piere Jesus Quiliche ◽  
Isabel Gómez ◽  
Jorge Sánchez ◽  
Mario Soberón ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Conformational Changes ◽  
Membrane Integrity ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Membrane Vesicles ◽  
Insect Midgut ◽  
Cry Proteins ◽  
Cry1ab Toxin ◽  
Domain I

Cry proteins produced by Bacillus thuringiensis are pore-forming toxins that disrupt the membrane integrity of insect midgut cells. The structure of such pore is unknown, but it has been shown that domain I is responsible for oligomerization, membrane insertion and pore formation activity. Specifically, it was proposed that some N-terminal α-helices are lost, leading to conformational changes that trigger oligomerization. We designed a series of mutants to further analyze the molecular rearrangements at the N-terminal region of Cry1Ab toxin that lead to oligomer assembly. For this purpose, we introduced Cys residues at specific positions within α-helices of domain I for their specific labeling with extrinsic fluorophores to perform Föster resonance energy transfer analysis to fluorescent labeled Lys residues located in Domains II–III, or for disulfide bridges formation to restrict mobility of conformational changes. Our data support that helix α-1 of domain I is cleaved out and swings away from the toxin core upon binding with Manduca sexta brush border membrane vesicles. That movement of helix α-2b is also required for the conformational changes involved in oligomerization. These observations are consistent with a model proposing that helices α-2b and α-3 form an extended helix α-3 necessary for oligomer assembly of Cry toxins.

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