Rational design and molecular diversity for the construction of anti-alpha-bungarotoxin antidotes with high affinity and in vivo efficiency.
The structure of peptide p6.7, a mimotope of the nicotinic receptor ligand site that binds alpha-bungarotoxin and neutralizes its toxicity, was compared to that of the acetylcholine binding protein. The central loop of p6.7, when complexed with alpha-bungarotoxin, fits the structure of the acetylcholine binding protein (AChBP) ligand site, whereas peptide terminal residues seem to be less involved in toxin binding. The minimal binding sequence of p6.7 was confirmed experimentally by synthesis of progressively deleted peptides. Affinity maturation was then achieved by random addition of residues flanking the minimal binding sequence and by selection of new alpha-bungarotoxin binding peptides on the basis of their dissociation kinetic rate. The tetra-branched forms of the resulting high-affinity peptides were effective as antidotes in vivo at a significantly lower dose than the tetra-branched lead peptide.
Lozzi
Luisa
L
Department of Molecular Biology, University of Siena, via Fiorentina 1, I-53100 Siena, Italy.
Lelli
Barbara
B
Runci
Ylenia
Y
Scali
Silvia
S
Bernini
Andrea
A
Falciani
Chiara
C
Pini
Alessandro
A
Niccolai
Neri
N
Neri
Paolo
P
Bracci
Luisa
L
D000595:Amino Acid Sequence; D000818:Animals; D000931:Antidotes / Q000138:chemical synthesis* / Q000378:metabolism; D001665:Binding Sites; D002038:Bungarotoxins / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism; D015195:Drug Design; D007700:Kinetics; D051379:Mice; D008958:Models, Molecular; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D019151:Peptide Library; D010455:Peptides / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment
C428944:AChBP protein, Lymnaea; D000931:Antidotes; D002038:Bungarotoxins; D002352:Carrier Proteins; D019151:Peptide Library; D010455:Peptides; D011978:Receptors, Nicotinic