3PB4: Crystal Structure Of The Catalytic Domain Of Human Golgi-Resident Glutaminyl Cyclase At Ph 6.0

Aberrant pyroglutamate formation at the N terminus of certain peptides and proteins, catalyzed by glutaminyl cyclases (QCs), is linked to some pathological conditions, such as Alzheimer disease. Recently, a glutaminyl cyclase (QC) inhibitor, PBD150, was shown to be able to reduce the deposition of pyroglutamate-modified amyloid-beta peptides in brain of transgenic mouse models of Alzheimer disease, leading to a significant improvement of learning and memory in those transgenic animals. Here, we report the 1.05-1.40 A resolution structures, solved by the sulfur single-wavelength anomalous dispersion phasing method, of the Golgi-luminal catalytic domain of the recently identified Golgi-resident QC (gQC) and its complex with PBD150. We also describe the high-resolution structures of secretory QC (sQC)-PBD150 complex and two other gQC-inhibitor complexes. gQC structure has a scaffold similar to that of sQC but with a relatively wider and negatively charged active site, suggesting a distinct substrate specificity from sQC. Upon binding to PBD150, a large loop movement in gQC allows the inhibitor to be tightly held in its active site primarily by hydrophobic interactions. Further comparisons of the inhibitor-bound structures revealed distinct interactions of the inhibitors with gQC and sQC, which are consistent with the results from our inhibitor assays reported here. Because gQC and sQC may play different biological roles in vivo, the different inhibitor binding modes allow the design of specific inhibitors toward gQC and sQC.
PDB ID: 3PB4Download
MMDB ID: 88370
PDB Deposition Date: 2010/10/20
Updated in MMDB: 2011/08
Experimental Method:
x-ray diffraction
Resolution: 1.13  Å
Source Organism:
Similar Structures:
Biological Unit for 3PB4: monomeric; determined by author and by software (PISA)
Molecular Components in 3PB4
Label Count Molecule
Protein (1 molecule)
Glutaminyl-peptide Cyclotransferase-like Protein(Gene symbol: QPCTL)
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB