Abstract
Two analogs of omega-conotoxin MVIIA, a 25mer peptide neurotoxin, were synthesized by replacing Lys2 or Tyr13 with Ala. The activities of synthetic analogs were estimated from the inhibitory action on 125I-omega-conotoxin GVIA binding to chick brain synaptic plasma membranes. As in the case of omega-conotoxin GVIA, replacement of Tyr13 resulted in an enormous reduction in activity. In contrast, substitution of Ala for Lys2 gave only a small effect. These results indicate that Tyr13 is a critical amino acid of omega-conotoxin MVIIA and GVIA for blocking N-type calcium channel function.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Brain / metabolism
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Calcium Channel Blockers / metabolism
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Calcium Channel Blockers / pharmacology*
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Chickens
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Circular Dichroism
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Kinetics
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Lysine
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Molecular Sequence Data
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Peptides / chemical synthesis
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Peptides / chemistry
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Peptides / metabolism
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Peptides / pharmacology*
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Peptides, Cyclic / chemical synthesis
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Peptides, Cyclic / chemistry
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Peptides, Cyclic / pharmacology
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Protein Conformation
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Synaptic Membranes / metabolism
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Tyrosine*
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omega-Conotoxin GVIA
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omega-Conotoxins*
Substances
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Calcium Channel Blockers
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Peptides
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Peptides, Cyclic
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omega-Conotoxins
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Tyrosine
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ziconotide
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omega-Conotoxin GVIA
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Lysine