Key Residues in the Nicotinic Acetylcholine Receptor β2 Subunit Contribute to α-Conotoxin LvIA Binding

Zhangsun, Dongting; Zhu, Xiaopeng; Wu, Yong; Hu, Yuanyan; Kaas, Quentin; Craik, David J.; McIntosh, J. Michael; Luo, Sulan

doi:10.1074/jbc.m114.632646

Cited by 18 publications

(18 citation statements)

References 41 publications

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“…For instance, the backbone tilt of conotoxin PnIA (A10L D14K) bound by hα7 nAChR is similar to the crystal structure of PnIA (A10L D14K) in complex with Ac-AChBP (PDB: 2BR8) [36]. This is favorable for using computer models to design and discover new potent α-conotoxins [2,3,51,52,53]. …”

Section: Introductionmentioning

confidence: 74%

“…A comparison of the Asn-11 and Asn-12 residues of the α-conotoxins in the crystal structure is shown in Figure 2. In Figure 2A, Asn-11 and Asn-12 of PnIA (A10L D14K), TxIA (A10L) and GIC form a hydrogen bond with the principal side (“+”-side, indicated in green, the residue-binding ligand is near loop C) [36] residues, Glu-191 and Tyr-91, and with the complementary side (“−“-side, indicated in blue, the residue-binding ligand is near loop E) [36,51] residues Arg-77. Mutating the residues of Asn-11 and Asn-12 to Ala resulted in the loss of affinity for Ac-AChBP [47].…”

Section: α-Conotoxin Residue-binding and Selectivity For Ac-achbpmentioning

confidence: 99%

“…From the structure of α-conotoxins in complex with Ac-AChBP, and as shown by many experiments, it is assumed that the α-conotoxin mutants were binding at a similar site of the receptor and displaying binding patterns similar to native conotoxins [47,49]. Most conotoxins share a common folding structure that is not expected to change upon binding, therefore “rigid” docking can be performed to determine the residues responsible for α-conotoxin’s binding and selectivity for nAChRs [41,50,51,52]. …”

Section: Introductionmentioning

confidence: 99%

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Residues Responsible for the Selectivity of α-Conotoxins for Ac-AChBP or nAChRs

Lin

Xiang

2016

Marine Drugs

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Nicotinic acetylcholine receptors (nAChRs) are targets for developing new drugs to treat severe pain, nicotine addiction, Alzheimer disease, epilepsy, etc. α-Conotoxins are biologically and chemically diverse. With 12–19 residues and two disulfides, they can be specifically selected for different nAChRs. Acetylcholine-binding proteins from Aplysia californica (Ac-AChBP) are homologous to the ligand-binding domains of nAChRs and pharmacologically similar. X-ray structures of the α-conotoxin in complex with Ac-AChBP in addition to computer modeling have helped to determine the binding site of the important residues of α-conotoxin and its affinity for nAChR subtypes. Here, we present the various α-conotoxin residues that are selective for Ac-AChBP or nAChRs by comparing the structures of α-conotoxins in complex with Ac-AChBP and by modeling α-conotoxins in complex with nAChRs. The knowledge of these binding sites will assist in the discovery and design of more potent and selective α-conotoxins as drug leads.

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Section: Introductionmentioning

confidence: 74%

Section: α-Conotoxin Residue-binding and Selectivity For Ac-achbpmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Residues Responsible for the Selectivity of α-Conotoxins for Ac-AChBP or nAChRs

Lin

Xiang

2016

Marine Drugs

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“…Residue 59 on the ␤ subunits of rat nAChRs has previously been identified as a determinant for ␣-conotoxin LvIA potency and wash-off kinetics (31). ␣-Conotoxin LvIA exhibited a 17-fold higher selectivity for rat ␣3␤2 over ␣3␤4, and the rat ␣3␤2[T59K] mutation further increased the the activity of the peptide by ϳ10-fold.…”

Section: Discussionmentioning

confidence: 99%

Key Structural Determinants in the Agonist Binding Loops of Human β2 and β4 Nicotinic Acetylcholine Receptor Subunits Contribute to α3β4 Subtype Selectivity of α-Conotoxins

Cuny

Kompella

Tae

et al. 2016

Journal of Biological Chemistry

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Edited by Paul Fraser␣-Conotoxins represent a large group of pharmacologically active peptides that antagonize nicotinic acetylcholine receptors (nAChRs). The ␣3␤4 nAChR, a predominant subtype in the peripheral nervous system, has been implicated in various pathophysiological conditions. As many ␣-conotoxins have multiple pharmacological targets, compounds specifically targeting individual nAChR subtypes are needed. In this study, we performed mutational analyses to evaluate the key structural components of human ␤2 and ␤4 nAChR subunits that determine ␣-conotoxin selectivity for ␣3␤4 nAChR. ␣-Conotoxin RegIIA was used to evaluate the impact of non-conserved human ␤2 and ␤4 residues on peptide affinity. Two mutations, ␣3␤2[T59K] and ␣3␤2[S113R], strongly enhanced RegIIA affinity compared with wild-type ␣3␤2, as seen by substantially increased inhibitory potency and slower off-rate kinetics. Opposite point mutations in ␣3␤4 had the contrary effect, emphasizing the importance of loop D residue 59 and loop E residue 113 as determinants for RegIIA affinity. Molecular dynamics simulation revealed the side chains of ␤4 Lys 59 and ␤4 Arg 113 formed hydrogen bonds with RegIIA loop 2 atoms, whereas the ␤2 Thr 59 and ␤2 Ser 113 side chains were not long enough to form such interactions. Residue ␤4 Arg 113 has been identified for the first time as a crucial component facilitating antagonist binding. Another ␣-conotoxin, AuIB, exhibited low activity at human ␣3␤2 and ␣3␤4 nAChRs. Molecular dynamics simulation indicated the key interactions with the ␤ subunit are different to RegIIA. Taken together, these data elucidate the interactions with specific individual ␤ subunit residues that critically determine affinity and pharmacological activity of ␣-conotoxins RegIIA and AuIB at human nAChRs.

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“…Recent studies of the molecular and structural basis for a-conotoxin BuIA and LvIA selectivity identified key residues on the b(2) interface of the b2 subunit that contribute to these toxins' activity and selectivity (Shiembob et al, 2006;Zhangsun et al, 2015), confirming that each a-conotoxin requires specific structural determinants for effective receptor binding.…”

Section: Methodsmentioning

confidence: 99%

Molecular Basis for Differential Sensitivity of α-Conotoxin RegIIA at Rat and Human Neuronal Nicotinic Acetylcholine Receptors

et al. 2015

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a-Conotoxins, as nicotinic acetylcholine receptor (nAChR) antagonists, are powerful tools for dissecting biologic processes and guiding drug development. The a3b2 and a3b4 nAChR subtypes are expressed in the central and peripheral nervous systems and play a critical role in various pathophysiological conditions ranging from nicotine addiction to the development and progression of lung cancer. Here we used the a4/7-conotoxin RegIIA, a disulfidebonded peptide from the venom of Conus regius, and its analog [N11A,N12A]RegIIA to probe the specific pharmacological properties of rat and human nAChR subtypes. nAChR subtypes were heterologously expressed in Xenopus oocytes and two-electrode voltage clamp recordings used to investigate the effects of the peptides on nAChR activity. RegIIA potently inhibited currents evoked by acetylcholine (ACh) at rat a3b2 (IC 50 5 10.7 nM), whereas a 70-fold lower potency was observed at human a3b2 nAChR (IC 50 5 704.1 nM). Conversely, there were no speciesspecific differences in sensitivity to RegIIA at the a3b4 nAChR. Receptor mutagenesis and molecular dynamics studies revealed that this difference can be attributed primarily to a single amino acid change: Glu198 on the rat a3 subunit corresponding to a proline on the human subunit. These findings reveal a novel species-and subunit-specific receptor-antagonist interaction.

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Key Residues in the Nicotinic Acetylcholine Receptor β2 Subunit Contribute to α-Conotoxin LvIA Binding

Cited by 18 publications

References 41 publications

Residues Responsible for the Selectivity of α-Conotoxins for Ac-AChBP or nAChRs

Residues Responsible for the Selectivity of α-Conotoxins for Ac-AChBP or nAChRs

Key Structural Determinants in the Agonist Binding Loops of Human β2 and β4 Nicotinic Acetylcholine Receptor Subunits Contribute to α3β4 Subtype Selectivity of α-Conotoxins

Molecular Basis for Differential Sensitivity of α-Conotoxin RegIIA at Rat and Human Neuronal Nicotinic Acetylcholine Receptors

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