Author/Editor		Križaj, I; Turk, D; Ritonja, A; Gubenšek, F
Title		Primary structure of ammodytoxin C further reveals the toxic site of ammodytoxin
Type		članek
Source		Biochim Biophys Acta
Vol. and No.		Letnik 999, št. 2
Publication year		1989
Volume		str. 198-202
Language		eng
Abstract		The sequence of ammodytoxin C, a presynaptically toxic, basic phospholipase A2 of Vipera ammodytes ammodytes venom was determined. The toxin differs only in two amino acid residues from the most toxic isotoxin ammodytoxin A and is 18-times less lethal. Ammodytoxin B which is 30-times less lethal than ammodytoxin A differs from it only in three amino acid residues. From the three-dimensional model of ammodytoxin A, it can be seen that mutated regions of ammodytoxin B and ammodytoxin C are on the surface, and relatively distant from each other. The observed decrease in toxicity of ammodytoxin C could be a consequence of changed charge in position 128 where a Lys is exchanged for Glu. The resulting change in electrostatic properties of the molecule which influences the orientation of the molecule during the approach to the charged nerve-terminal membrane might be responsible for the observed decrease in toxicity.
Descriptors		PHOSPHOLIPASES PHOSPHOLIPASES A VIPER VENOMS AMINO ACID SEQUENCE MODELS, MOLECULAR MOLECULAR SEQUENCE DATA PROTEIN CONFORMATION SEQUENCE HOMOLOGY, NUCLEIC ACID SOFTWARE VIPER VENOMS