1agg

THE SOLUTION STRUCTURE OF OMEGA-AGA-IVB, A P-TYPE CALCIUM CHANNEL ANTAGONIST FROM THE VENOM OF AGELENOPSIS APERTATHE SOLUTION STRUCTURE OF OMEGA-AGA-IVB, A P-TYPE CALCIUM CHANNEL ANTAGONIST FROM THE VENOM OF AGELENOPSIS APERTA

Structural highlights 1agg is a 1 chain structure with sequence from Agelenopsis aperta. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TX23B_AGEAP Antagonist of voltage-gated Cav2.1/CACNA1A (P-type) calcium channels. Paralyzes insect by blocking neuromuscular transmission. Publication Abstract from PubMed The 48 amino acid peptides omega-Aga-IVA and omega-Aga-IVB are the first agents known to specifically block P-type calcium channels in mammalian brain, thus complementing the existing suite of pharmacological tools used for characterizing calcium channels. These peptides provide a new set of probes for studies aimed at elucidating the structural basis underlying the subtype specificity of calcium channel antagonists. We used 288 NMR-derived constraints in a protocol combining distance geometry and molecular dynamics employing the program DGII, followed by energy minimization with Discover to derive the three-dimensional structure of omega-Aga-IVB. The toxin consists of a well-defined core region, comprising seven solvent-shielded residues and a well-defined triple-stranded beta-sheet. Four loop regions have average backbone rms deviations between 0.38 and 1.31 A, two of which are well-defined type-II beta-turns. Other structural features include disordered C- and N-termini and several conserved basic amino acids that are clustered on one face of the molecule. The reported structure suggests a possible surface for interaction with the channel. This surface contains amino acids that are identical to those of another known P-type calcium channel antagonist, omega-Aga-IVA, and is rich in basic residues that may have a role in binding to the anionic sites in the extracellular regions of the calcium channel. The solution structure of omega-Aga-IVB, a P-type calcium channel antagonist from venom of the funnel web spider, Agelenopsis aperta.,Reily MD, Thanabal V, Adams ME J Biomol NMR. 1995 Feb;5(2):122-32. PMID:7703698 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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