2XUJ

CRYSTAL STRUCTURE OF MACHE-Y337A-TZ2PA6 SYN COMPLEX (1 MTH)

Summary for 2XUJ

• Entry DOI: 10.2210/pdb2xuj/pdb
• Related: 1C2B 1C2O 1J06 1J07 1KU6 1MAA 1MAH 1N5M 1N5R 1Q83 1Q84 2C0P 2C0Q 2H9Y 2HA0 2HA2 2HA3 2HA4 2HA5 2HA6 2HA7 2JEY 2JEZ 2JF0 2JGE 2JGF 2JGG 2JGH 2JGI 2JGJ 2JGK 2JGL 2JGM 2WHP 2WHQ 2WHR 2WLS 2WU3 2WU4 2XUD 2XUF 2XUG 2XUH 2XUI 2XUK 2XUO 2XUP
• Descriptor: ACETYLCHOLINESTERASE, 2-acetamido-2-deoxy-beta-D-glucopyranose, HEXAETHYLENE GLYCOL, ... (5 entities in total)
• Functional Keywords: hydrolase, hydrolase fold, click chemistry
• Biological source: MUS MUSCULUS (HOUSE MOUSE)
• Total number of polymer chains: 2
• Total formula weight: 121172.05

Authors

Bourne, Y.,Radic, Z.,Taylor, P.,Marchot, P. (deposition date: 2010-10-19, release date: 2010-12-08, Last modification date: 2024-10-16)

Primary citation

Bourne, Y.,Radic, Z.,Taylor, P.,Marchot, P.
Conformational Remodeling of Femtomolar Inhibitor-Acetylcholinesterase Complexes in the Crystalline State
J.Am.Chem.Soc., 132:18292-, 2010

PubMed Abstract: The active center of acetylcholinesterase (AChE), a target site for competitive inhibitors, resides centrosymmetric to the subunit at the base of a deep, narrow gorge lined by aromatic residues. At the gorge entry, a peripheral site encompasses overlapping binding loci for noncompetitive inhibitors, which alter substrate access to the gorge. The click-chemistry inhibitor TZ2PA6 links the active center ligand, tacrine, to the peripheral site ligand, propidium, through a biorthogonal reaction of an acetylene and an azide that forms either a syn1 or an anti1 triazole. Compared with wild-type mouse AChE, a Tyr337Ala mutant displays full catalytic activity, albeit with 2-3 orders of magnitude higher affinities for the TZ2PA6 syn1 and anti1 regioisomers, reflected in low femtomolar K(d) values, diffusion-limited association, and dissociation half-times greater than 1 month and 1 week, respectively. Three structures of each of the co-crystallized syn1 and anti1 complexes of the Tyr337Ala mutant were solved at three distinct times of crystal maturation, consistent with or exceeding the half-lives of the complexes in solution, while crystalline complexes obtained from soaked Tyr337Ala crystals led to picturing "freshly formed" complexes. The structures, at 2.55-2.75 Å resolution, reveal a range of unprecedented conformations of the bound regioisomers, not observed in the wild-type AChE complexes, associated with concerted positional rearrangements of side chains in the enzyme gorge. Moreover, time-dependent conformational remodeling of the crystalline complexes appears to correlate with the dissociation half-times of the solution complexes. Hence, for the tight-binding TZ2PA6 inhibitors, the initial complexes kinetically driven in solution slowly form more stable complexes governed by thermodynamic equilibrium and observable in mature crystals.

PubMed: 21090615
DOI: 10.1021/JA106820E

Experimental method

X-RAY DIFFRACTION (2.65 Å)