Consensus sequence L/PKSSLL mimics crucial epitope on Loop III of Taiwan cobra cardiotoxin

Wang, Ping-Chieh; Loh, Kah-Sin; Lin, Shu-Ping; Chien, Tzu-Ling; Chiang, Jen-Ron; Hsieh, Wen-Chin; Miao, Bor-Lin; Su, Cheng-Fu; Yang, Wen-Jen

doi:10.1016/j.bbrc.2009.07.097

Cited by 4 publications

(3 citation statements)

References 18 publications

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“…Among the peptides tested, the reactivity of antibody with CTX A3 43–57 was more dominant than the adjacent peptides, which suggests that the sequence of SSLLVKY (residues 45–51 of CTX A3) was the potential B-cell epitope. Similar to other cytotoxins, CTX A3 contains hydrophobic LL residues flanked by polar amino acids and forms a cytolytic region on the tip of loop III, which enables the toxin to anchor the cell membrane and perturbs its integrity [ 36 , 38 , 39 , 40 ]. The multiple sequence alignment also revealed that a high amount of conserved residue was clustered in the C-terminal region of these cytotoxic 3FTXs.…”

Section: Resultsmentioning

confidence: 99%

Identification of Immunoreactive Peptides of Toxins to Simultaneously Assess the Neutralization Potency of Antivenoms against Neurotoxicity and Cytotoxicity of Naja atra Venom

Liu

Lin

et al. 2017

Toxins

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Assessing the neutralization capability of nonlethal but medically relevant toxins in venom has been a challenging task. Nowadays, neutralization efficacy is evaluated based simply on the survival rates of animals injected with antivenom together with a predefined dose of venom, which can determine potency against neurotoxicity but not validate the capability to neutralize cytotoxin-induced complications. In this study, a high correlation with in-vivo and in-vitro neutralization assays was established using the immunoreactive peptides identified from short-chain neurotoxin and cytotoxin A3. These peptides contain conserved residues associated with toxin activities and a competition assay indicated that these peptides could specifically block the antibody binding to toxin and affect the neutralization potency of antivenom. Moreover, the titers of peptide-specific antibody in antivenoms or mouse antisera were determined by enzyme-linked immunosorbent assay (ELISA) simultaneously, and the results indicated that Taiwanese bivalent antivenom (BAV) and Vietnamese snake antivenom-Naja (SAV-Naja) exhibited superior neutralization potency against the lethal effect of short-chain neurotoxin (sNTX) and cytotoxicity of cardiotoxin/cytotoxin (CTX), respectively. Thus, the reported peptide ELISA shows not only its potential for antivenom prequalification use, but also its capability of justifying the cross-neutralization potency of antivenoms against Naja atra venom toxicity.

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Section: Resultsmentioning

confidence: 99%

Identification of Immunoreactive Peptides of Toxins to Simultaneously Assess the Neutralization Potency of Antivenoms against Neurotoxicity and Cytotoxicity of Naja atra Venom

Liu

Lin

et al. 2017

Toxins

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“…Thus, based on the observed correlations between variations in amino acid sequences of CTs and their depolarization activities on cultural skeletal muscle, Hodges et al [ 51 ] revealed the importance of some residues, including Lys44 and Lys50 attributed here to the L3 site. Furthermore, a consensus sequence L/PKSSLL, which mimics an epitope on the loop III of CT A3 (including Pro43, Lys44, and Ser45 of the L3 site) was recently identified as a crucial neutralizing epitope for antivenin binding [ 52 ]. However, we should mention that in many cases the functional importance of particular residues observed in experiments does not mean that these residues are necessarily involved in lipid binding.…”

Section: Discussionmentioning

confidence: 92%

Snake Cytotoxins Bind to Membranes via Interactions with Phosphatidylserine Head Groups of Lipids

et al. 2011

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The major representatives of Elapidae snake venom, cytotoxins (CTs), share similar three-fingered fold and exert diverse range of biological activities against various cell types. CT-induced cell death starts from the membrane recognition process, whose molecular details remain unclear. It is known, however, that the presence of anionic lipids in cell membranes is one of the important factors determining CT-membrane binding. In this work, we therefore investigated specific interactions between one of the most abundant of such lipids, phosphatidylserine (PS), and CT 4 of Naja kaouthia using a combined, experimental and modeling, approach. It was shown that incorporation of PS into zwitterionic liposomes greatly increased the membrane-damaging activity of CT 4 measured by the release of the liposome-entrapped calcein fluorescent dye. The CT-induced leakage rate depends on the PS concentration with a maximum at approximately 20% PS. Interestingly, the effects observed for PS were much more pronounced than those measured for another anionic lipid, sulfatide. To delineate the potential PS binding sites on CT 4 and estimate their relative affinities, a series of computer simulations was performed for the systems containing the head group of PS and different spatial models of CT 4 in aqueous solution and in an implicit membrane. This was done using an original hybrid computational protocol implementing docking, Monte Carlo and molecular dynamics simulations. As a result, at least three putative PS-binding sites with different affinities to PS molecule were delineated. Being located in different parts of the CT molecule, these anion-binding sites can potentially facilitate and modulate the multi-step process of the toxin insertion into lipid bilayers. This feature together with the diverse binding affinities of the sites to a wide variety of anionic targets on the membrane surface appears to be functionally meaningful and may adjust CT action against different types of cells.

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“…On the other hand, the L3 site located near loop III has a structure similar to that of the M site: the backbone atoms of this site’s residues (P43, Y51, and C53) form hydrogen bonds with the lipid’s polar head, which is additionally supported by an electrostatic interaction with the ionic groups of lysine residues (K44 and K50). Recently, a consensus sequence L/PKSSLL based on a peptide sequence alignment (related to antibodies neutralizing N. atra venom) revealed by phage display has been proposed as an epitope involved in the action of CT A3 from N. atra venom [34]. This epitope corresponds to a fragment of the loop III sequence and contains the L3 site residues (P43–S45).…”

Section: Discussionmentioning

confidence: 99%

Anionic Lipids: Determinants of Binding Cytotoxins from Snake Venom on the Surface of Cell Membranes

Konshina¹,

Boldyrev²,

Omelkov³

et al. 2010

Acta Naturae

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The cytotoxic properties of cytotoxins (CTs) from snake venom are mediated by their interaction with the cell membrane. The hydrophobic pattern containing the tips of loops I–III and flanked by polar residues is known to be a membrane–binding motif of CTs. However, this is not enough to explain the difference in activity among various CTs which are similar in sequence and in 3D structure. The mechanism of further CT–membrane interaction leading to pore formation and cell death still remains unknown. Published experimental data on the specific interaction between CT and low molecular weight anionic components (sulphatide) of the bilayer point to the existence of corresponding ligand binding sites on the surface of toxin molecules. In this work we study the membrane–lytic properties of CT I, CT II (Naja oxiana), and Ct 4 (Naja kaouthia), which belong to different structural and functional types (P– and S–type) of CTs, by measuring the intensity of a fluorescent dye, calcein released from liposomes containing a phosphatidylserine (PS) lipid as an anionic component. Using molecular docking simulations, we find and characterize three sites in CT molecules that can potentially bind the PS polar head. Based on the data obtained, we suggest a hypothesis that CTs can specifically interact with one or more of the anionic lipids (in particular, with PS) contained in the membrane, thus facilitating the interaction between CTs and the lipid bilayer of a cell membrane.

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Consensus sequence L/PKSSLL mimics crucial epitope on Loop III of Taiwan cobra cardiotoxin

Cited by 4 publications

References 18 publications

Identification of Immunoreactive Peptides of Toxins to Simultaneously Assess the Neutralization Potency of Antivenoms against Neurotoxicity and Cytotoxicity of Naja atra Venom

Identification of Immunoreactive Peptides of Toxins to Simultaneously Assess the Neutralization Potency of Antivenoms against Neurotoxicity and Cytotoxicity of Naja atra Venom

Snake Cytotoxins Bind to Membranes via Interactions with Phosphatidylserine Head Groups of Lipids

Anionic Lipids: Determinants of Binding Cytotoxins from Snake Venom on the Surface of Cell Membranes

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