TETANO

TETANO

TETANO NEONATALE

BOTULISMO

TETANUS
SNC
spastic paralysis
BOTULISM
SNP
flaccid paralisys

NMJ STRUCTURE

MECCANISMO DI INTOSSICAZIONE INTRACELLULARE

SNARE COMPLEX

sinapsi di controllo
sinapsi intossicata

IDENTIFICATION OF KEY RESIDUES OF THE ENDOPEPTIDASE
ACTIVITY OF TeNT AND BoNT/A LIGHT CHAINS

SITE-DIRECTED MUTAGENESIS
Ala
Glu 261
in BoNT/A
Glu 271
in TeNT
Asp
Ala
Ala
Phe 265
in BoNT/A
Tyr 365
in BoNT/A
Tyr 375
in TeNT
Ala
Phe
Ala

PROTEOLYTIC ACTIVITY OF TeNT
MUTANTS
% of proteolysis
100
80
60
40
20
0
0 1 2 3
time (hours)
LC
Tyr375Phe
Tyr375Ala
% of proteolysis
100
80
60
40
20
0
0 1 2 3
time (hours)
LC
Glu271Asp
Glu271Ala

PROTEOLYTIC ACTIVITY OF BoNT/A
MUTANTS
% of proteolysis
100
90
80
70
60
50
40
30
20
10
0
0 20 40 60 80 100 120
Time (min)
Lc
Glu261Ala
Tyr365Ala
Phe265Ala

CONCLUSIONS OF THE MUTAGENESIS STUDY
- Glu261 in BoNT/A and the correspondant residue in TeNT
is the fourth ligand of the catalytic zinc
- Tyr365 in BoNT/A and the correspondant residue in TeNT
has an important role in assisting the hydrolysis
-Phe266
might have a role in substrate binding