STRUCTURE AND FUNCTION OF Α-Bungarotoxin

Moise, Leonard; Zeng, Haoyu; Caffery, Philip M.; Rogowski, Robert S.; Hawrot, Edward

doi:10.1081/txr-120014407

Cited by 12 publications

(20 citation statements)

References 77 publications

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“…We have observed, however, that ␤4/␣1 [11]Loop-C-bearing receptors with ␣4 subunits substituting for ␣3 are somewhat less sensitive to Bgtx inhibition, suggesting that the (Ϫ) face of the ␣ subunit may directly contribute to the introduced Bgtx binding site. 2 This would suggest that it is binding to the ␤(ϩ)␣(Ϫ) interface that is responsible for the observed functional block.…”

Section: Bgtx Binds To Intact Oocytes Expressing Nachrs Containing Thmentioning

confidence: 99%

“…2 In addition, in those cases in which high affinity Bgtx binding is conferred in the absence of pharmacological sensitivity, such constructs would be of considerable utility for studies of receptor localization and metabolism given the many commercially available reporter group derivatives of Bgtx. The relatively small size of Bgtx (ϳ8 kDa) as compared with antibodies may offer a further advantage in tissue penetrance and accessibility.…”

Section: Bgtx Binds To Intact Oocytes Expressing Nachrs Containing Thmentioning

confidence: 99%

“…The biochemical and molecular characterization of muscle nAChRs, the first representatives of the superfamily to be characterized in molecular terms, has been greatly facilitated by the availability of highly specific snake venom-derived ␣-neurotoxins, such as ␣-bungarotoxin (Bgtx). These small proteins are high affinity competitive antagonists that interact with a subset of agonist binding determinants to disrupt agonist binding (2). Furthermore, the commercial availability of a large number of diversely labeled conjugates of Bgtx has led to major advances in the understanding of the biogenesis and developmental regulation of muscle nAChRs (3).…”

mentioning

confidence: 99%

“…These studies, together with observations that Bgtx binds with high affinity to isolated short peptide fragments derived from ␣1 Loop C, led us to speculate that short sequences derived from ␣1 Loop C might be effective in transferring Bgtx sensitivity to a more distantly related target, such as the nicotinic ␤4 subunit, one of the widely expressed neuronal non-␣ subunits. If successful, we reasoned that such a sequence, which we term a pharmatope in analogy to epitope tagging, could provide a general tool for introducing pharmacological sensitivity into membrane proteins (2).…”

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confidence: 99%

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A Novel Pharmatope Tag Inserted into the β4 Subunit Confers Allosteric Modulation to Neuronal Nicotinic Receptors

Sanders

Hawrot

2004

Journal of Biological Chemistry

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␣-Bungarotoxin, the classic nicotinic antagonist, has high specificity for muscle type ␣1 subunits in nicotinic acetylcholine receptors. In this study, we show that an 11-amino-acid pharmatope sequence, containing residues important for ␣-bungarotoxin binding to ␣1, confers functional ␣-bungarotoxin sensitivity when strategically placed into a neuronal non-␣ subunit, normally insensitive to this toxin. Remarkably, the mechanism of toxin inhibition is allosteric, not competitive as with neuromuscular nicotinic receptors. Our findings argue that ␣-bungarotoxin binding to the pharmatope, inserted at a subunit-subunit interface diametrically distinct from the agonist binding site, interferes with subunit interface movements critical for receptor activation. Our results, taken together with the structural similarities between nicotinic and GABA A receptors, suggest that this allosteric mechanism is conserved in the Cys-loop ion channel family. Furthermore, as a general strategy, the engineering of allosteric inhibitory sites through pharmatope tagging offers a powerful new tool for the study of membrane proteins.

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Section: Bgtx Binds To Intact Oocytes Expressing Nachrs Containing Thmentioning

confidence: 99%

Section: Bgtx Binds To Intact Oocytes Expressing Nachrs Containing Thmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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A Novel Pharmatope Tag Inserted into the β4 Subunit Confers Allosteric Modulation to Neuronal Nicotinic Receptors

Sanders

Hawrot

2004

Journal of Biological Chemistry

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“…Furthermore, NMR analysis of free a -bungarotoxin and a -bungarotoxin in complex with short cognate peptides of the nAChR toxin-binding region revealed that the cyclic conformation of the tip of loop II was a dynamic entity (85). This flexibility of loop II would enable long-chain a -neurotoxins to accommodate substantial structural deviations and adopt alternate conformations in order to bind to diverse receptor subtypes (47,86).…”

Section: Conformational Determinants Of Structure-function Of A-nmentioning

confidence: 99%

Three-Finger α-Neurotoxins and the Nicotinic Acetylcholine Receptor, Forty Years On

2004

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Abstract. The discovery, about forty years ago, of a -bungarotoxin, a three-finger a -neurotoxin from Bungarus multicinctus venom, enabled the isolation of the nicotinic acetylcholine receptor (nAChR), making it one of the most thoroughly characterized receptors today. Since then, the sites of interaction between a -neurotoxins and nAChRs have largely been delineated, revealing the remarkable plasticity of the three-finger toxin fold that has optimally evolved to utilize different combinations of functional groups to generate a panoply of target specificities to discern subtle differences between nAChR subtypes. New facets in toxinology have now broadened the scope for the use of a-neurotoxins in scientific discovery. For instance, the development of short, combinatorial library-derived, synthetic peptides that bind with subnanomolar affinity to a -bungarotoxin and prevent its interaction with muscle nAChRs has led to the in vivo neutralization of experimental a -bungarotoxin envenomation, while the successful introduction of pharmatopes bearing "a -bungarotoxin-sensitive sites" into toxin-insensitive nAChRs has permitted the use of various a -neurotoxin tags to localize and characterize new receptor subtypes. More ambitious strategies can now be envisaged for engineering rationally designed novel activities on three-finger toxin scaffolds to generate lead peptides of therapeutic value that target the nicotinic pharmacopoeia. This review details the progress made towards achieving this goal.

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Peptide Toxin Inhibition of Voltage Gated Calcium Channels

McDonough¹

2004

Calcium Channel Pharmacology

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STRUCTURE AND FUNCTION OF Α-Bungarotoxin

Cited by 12 publications

References 77 publications

A Novel Pharmatope Tag Inserted into the β4 Subunit Confers Allosteric Modulation to Neuronal Nicotinic Receptors

A Novel Pharmatope Tag Inserted into the β4 Subunit Confers Allosteric Modulation to Neuronal Nicotinic Receptors

Three-Finger α-Neurotoxins and the Nicotinic Acetylcholine Receptor, Forty Years On

Peptide Toxin Inhibition of Voltage Gated Calcium Channels

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