PDBsum entry 1zl6

Hydrolase

PDB id: 1zl6

Contents

Protein chains

400 a.a. *

Ligands

SO4

Metals

_ZN ×2

Waters ×207

* Residue conservation analysis

PDB id:

1zl6

Name:

Hydrolase

Title:

Crystal structure of tyr350ala mutant of clostridium botulinum neurotoxin e catalytic domain

Structure:

Botulinum neurotoxin type e. Chain: a, b. Fragment: catalytic domain (residues 2-421). Engineered: yes. Mutation: yes

Source:

Clostridium botulinum. Organism_taxid: 1491. Strain: nctc-11219. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Biol. unit:

Dimer (from PQS)

Resolution:

2.40Å R-factor: 0.235 R-free: 0.284

Authors:

R.Agarwal,T.Binz,S.Swaminathan

Key ref:

R.Agarwal et al. (2005). Analysis of active site residues of botulinum neurotoxin E by mutational, functional, and structural studies: Glu335Gln is an apoenzyme. Biochemistry, 44, 8291-8302. PubMed id: 15938619 DOI: 10.1021/bi050253a

Date:

05-May-05 Release date: 28-Jun-05

Protein chains

Q00496  (BXE_CLOBO) -  Botulinum neurotoxin type E from Clostridium botulinum

Seq: 1251 a.a.

Struc: 400 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.4.24.69 - bontoxilysin.
• Reaction: Limited hydrolysis of proteins of the neuroexocytosis apparatus, synaptobrevins, SNAP25 or syntaxin. No detected action on small molecule substrates.
• Cofactor: Zn(2+)

DOI no: 10.1021/bi050253a

Biochemistry 44:8291-8302 (2005)

PubMed id: 15938619

Analysis of active site residues of botulinum neurotoxin E by mutational, functional, and structural studies: Glu335Gln is an apoenzyme.

R.Agarwal, T.Binz, S.Swaminathan.

ABSTRACT

Clostridial neurotoxins comprising the seven serotypes of botulinum neurotoxins and tetanus neurotoxin are the most potent toxins known to humans. Their potency coupled with their specificity and selectivity underscores the importance in understanding their mechanism of action in order to develop a strategy for designing counter measures against them. To develop an effective vaccine against the toxin, it is imperative to achieve an inactive form of the protein which preserves the overall conformation and immunogenicity. Inactive mutants can be achieved either by targeting active site residues or by modifying the surface charges farther away from the active site. The latter affects the long-range forces such as electrostatic potentials in a subtle way without disturbing the structural integrity of the toxin causing some drastic changes in the activity/environment. Here we report structural and biochemical analysis on several mutations on Clostridium botulinum neurotoxin type E light chain with at least two producing dramatic effects: Glu335Gln causes the toxin to transform into a persistent apoenzyme devoid of zinc, and Tyr350Ala has no hydrolytic activity. The structural analysis of several mutants has led to a better understanding of the catalytic mechanism of this family of proteins. The residues forming the S1' subsite have been identified by comparing this structure with a thermolysin-inhibitor complex structure.