Biochemical characterization of cysteine-rich peptides from Oxyopes sp. venom that block calcium ion channels.
Oxytoxins (OxyTx1 and OxyTx2) are disulfide-rich peptides isolated from the venom of the spider Oxyopes lineatus that block voltage-sensitive calcium ion channels (VSCCs). OxyTx1 was identified previously and isolated from the related spider Oxyopes kitabensis; however, its pharmacology was unknown. OxyTx1 and OxyTx2 contain 69 and 55 amino acid residues with molecular masses of 8058.2 and 6175.2Da, respectively. Oxytoxins contain five disulfide bridges, are amidated at their C-terminus, antagonize P/Q-, N- or L-type VSCCs, and have low amino acid identity to known VSCC blockers from arthropod venoms. OxyTx1 is not specific for VSCCs subtypes when compared to the classical P/Q-type blocker omega-AgaIVA, but OxyTx1 has higher paralytic activity towards Spodoptera litura larvae. Because of their structural and biochemical characteristics OxyTx1 and OxyTx2 may represent a new family of insecticidal peptides.
Villegas
Elba
E
Centro de Investigación en Biotecnología - UAEM, Av. Universidad 2001, Cuernavaca, Morelos 62210, México. elbav@buzon.uaem.mx
Adachi-Akahane
Satomi
S
Bosmans
Frank
F
Tytgat
Jan
J
Nakajima
Terumi
T
Corzo
Gerardo
G
D000595:Amino Acid Sequence; D000818:Animals; D002121:Calcium Channel Blockers / Q000737:chemistry* / Q000494:pharmacology; D020864:Calcium Channels, N-Type / Q000187:drug effects / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002942:Circular Dichroism; D006224:Cricetinae; D003545:Cysteine / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D019476:Insect Proteins / Q000737:chemistry* / Q000494:pharmacology; D008969:Molecular Sequence Data; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D009498:Neurotoxins / Q000737:chemistry* / Q000494:pharmacology; D010063:Ovum / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D010455:Peptides / Q000737:chemistry*; D016415:Sequence Alignment; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013111:Spider Venoms / Q000737:chemistry* / Q000494:pharmacology; D013112:Spiders / Q000378:metabolism*; D014982:Xenopus laevis
D002121:Calcium Channel Blockers; D020864:Calcium Channels, N-Type; D019476:Insect Proteins; D009498:Neurotoxins; D010455:Peptides; D013111:Spider Venoms; D003545:Cysteine