PDBsum entry: 2ha6

Hydrolase

PDB id: 2ha6

Contents

Protein chains

536 a.a. *

Ligands

SCK ×4

P6G

ACY

Waters ×624

* Residue conservation analysis

PDB id:

2ha6

Name:

Hydrolase

Title:

Crystal structure of mutant s203a of mouse acetylcholinester complexed with succinylcholine

Structure:

Acetylcholinesterase. Chain: a, b. Fragment: catalytic domain. Synonym: ache. Engineered: yes. Mutation: yes

Source:

Mus musculus. House mouse. Organism_taxid: 10090. Expressed in: homo sapiens. Expression_system_taxid: 9606. Expression_system_variant: lambda zap. Expression_system_cell_line: hek 293. Expression_system_cell: human embryonic kidney cells (hek)

Resolution:

2.25Å R-factor: 0.178 R-free: 0.198

Authors:

Y.Bourne,Z.Radic,G.Sulzenbacher,E.Kim,P.Taylor,P.Marchot

Key ref:

Y.Bourne et al. (2006). Substrate and product trafficking through the active center gorge of acetylcholinesterase analyzed by crystallography and equilibrium binding. J Biol Chem, 281, 29256-29267. PubMed id: 16837465 DOI: 10.1074/jbc.M603018200

Date:

12-Jun-06 Release date: 18-Jul-06

Protein chains

P21836  (ACES_MOUSE) -  Acetylcholinesterase

Seq: 614 a.a.

Struc: 536 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.3.1.1.7 - Acetylcholinesterase.
• Reaction: Acetylcholine + H₂O = choline + acetate

Acetylcholine (Bound ligand (Het Group name = SCK) matches with 50.00% similarity) + H(2)O = choline + acetate (Bound ligand (Het Group name = ACY) corresponds exactly)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Cellular component: extracellular region (12 terms)
• Biological process: cell adhesion (9 terms)
• Biochemical function: hydrolase activity (11 terms)

reference

DOI no: 10.1074/jbc.M603018200

J Biol Chem 281:29256-29267 (2006)

PubMed id: 16837465

Substrate and product trafficking through the active center gorge of acetylcholinesterase analyzed by crystallography and equilibrium binding.

Y.Bourne, Z.Radic, G.Sulzenbacher, E.Kim, P.Taylor, P.Marchot.

ABSTRACT

Hydrolysis of acetylcholine catalyzed by acetylcholinesterase (AChE), one of the most efficient enzymes in nature, occurs at the base of a deep and narrow active center gorge. At the entrance of the gorge, the peripheral anionic site provides a binding locus for allosteric ligands, including substrates. To date, no structural information on substrate entry to the active center from the peripheral site of AChE or its subsequent egress has been reported. Complementary crystal structures of mouse AChE and an inactive mouse AChE mutant with a substituted catalytic serine (S203A), in various complexes with four substrates (acetylcholine, acetylthiocholine, succinyldicholine, and butyrylthiocholine), two non-hydrolyzable substrate analogues (m-(N,N,N-trimethylammonio)-trifluoroacetophenone and 4-ketoamyltrimethylammonium), and one reaction product (choline) were solved in the 2.05-2.65-A resolution range. These structures, supported by binding and inhibition data obtained on the same complexes, reveal the successive positions and orientations of the substrates bound to the peripheral site and proceeding within the gorge toward the active site, the conformations of the presumed transition state for acylation and the acyl-enzyme intermediate, and the positions and orientations of the dissociating and egressing products. Moreover, the structures of the AChE mutant in complexes with acetylthiocholine and succinyldicholine reveal additional substrate binding sites on the enzyme surface, distal to the gorge entry. Hence, we provide a comprehensive set of structural snapshots of the steps leading to the intermediates of catalysis and the potential regulation by substrate binding to various allosteric sites at the enzyme surface.

Selected figure(s)

Figure 1.
FIGURE 1. Overall view of the mAChE subunit. mAChE is viewed down into the gorge with one 4K-TMA molecule (magenta atoms and surface) bound in the active site (labeled AS) and a second 4K-TMA molecule (orange atoms and surface) bound at the PAS (blue Trp^286 and surface). The long loop Cys^69-Cys^96 is in orange and the disulfide bounds in green. The GlcNac moieties linked to Asn^350 on same face as the gorge entrance (bottom) and Asn^464 in the back door region (right) are shown with red oxygens and blue nitrogens. N and C termini are indicated.

Figure 3.
FIGURE 3. Comparison of active site-bound ligands. Overlays of 4K-TMA bound to mAChE (magenta molecule and surface) with ACh (green) docked in TcAChE (PDB entry 2ACE) (A), choline bound to mAChE (magenta molecule and surface) with choline bound to BChE (orange) (entry 1P0M), (B), ATCh bound to the S203Ala mutant (magenta molecule and surface) with BTCh (orange) and soman (blue) bound to BChE (entry 1P0P) (C). Note the Tyr337Ala mutation in BChE.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2006, 281, 29256-29267) copyright 2006.

Figures were selected by an automated process.