 |
PDBsum entry 3hg2
|
|
|
|
References listed in PDB file
|
 |
|
Key reference
|
|
|
Title
|
|
Catalytic mechanism of human alpha-Galactosidase.
|
|
|
Authors
|
|
A.I.Guce,
N.E.Clark,
E.N.Salgado,
D.R.Ivanen,
A.A.Kulminskaya,
H.Brumer,
S.C.Garman.
|
|
|
Ref.
|
|
J Biol Chem, 2010,
285,
3625-3632.
|
|
|
PubMed id
|
|
|
|
|
|
|
|
|
Abstract
|
|
|
The enzyme alpha-galactosidase (alpha-GAL, also known as alpha-GAL A; E.C.
3.2.1.22) is responsible for the breakdown of alpha-galactosides in the
lysosome. Defects in human alpha-GAL lead to the development of Fabry disease, a
lysosomal storage disorder characterized by the buildup of alpha-galactosylated
substrates in the tissues. alpha-GAL is an active target of clinical research:
there are currently two treatment options for Fabry disease, recombinant enzyme
replacement therapy (approved in the United States in 2003) and pharmacological
chaperone therapy (currently in clinical trials). Previously, we have reported
the structure of human alpha-GAL, which revealed the overall structure of the
enzyme and established the locations of hundreds of mutations that lead to the
development of Fabry disease. Here, we describe the catalytic mechanism of the
enzyme derived from x-ray crystal structures of each of the four stages of the
double displacement reaction mechanism. Use of a
difluoro-alpha-galactopyranoside allowed trapping of a covalent intermediate.
The ensemble of structures reveals distortion of the ligand into a (1)S(3) skew
(or twist) boat conformation in the middle of the reaction cycle. The high
resolution structures of each step in the catalytic cycle will allow for
improved drug design efforts on alpha-GAL and other glycoside hydrolase family
27 enzymes by developing ligands that specifically target different states of
the catalytic cycle. Additionally, the structures revealed a second
ligand-binding site suitable for targeting by novel pharmacological chaperones.
|
|
|
|
|
|
|
