The C-terminal region of ammodytoxins is important but not sufficient for neurotoxicity.
Ammodytoxins (Atxs) are presynaptically acting snake venom phospholipase A2 (PLA2) toxins the molecular mechanism of whose neurotoxicity is not completely understood. Two chimeric PLA2s were prepared by replacing the C-terminal part of a nontoxic venom PLA2, ammodytin I2, with that of AtxA(K108N). The chimeras were not toxic, but were able to bind strongly to an Atxs-specific neuronal receptor, R25. They also showed an increased affinity for calmodulin, a recently identified high-affinity binding protein for Atxs, whereas affinity for a neuronal M-type PLA2 receptor remained largely unchanged. The results show that the C-terminal region of Atxs, which is known to be involved in neurotoxicity, is critical for their interaction with specific binding proteins, but that some other part of the molecule also contributes to toxicity.
Prijatelj
Petra
P
Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia.
Krizaj
Igor
I
Kralj
Bogdan
B
Gubensek
Franc
F
Pungercar
Joze
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D002942:Circular Dichroism; D017931:DNA Primers; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009420:Nervous System / Q000187:drug effects*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000633:toxicity; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D014757:Viper Venoms / Q000737:chemistry / Q000633:toxicity*
D017931:DNA Primers; D011993:Recombinant Fusion Proteins; D014757:Viper Venoms; C068117:ammodytoxin A