X‐ray structure of human acid‐β‐glucosidase, the defective enzyme in Gaucher disease

Abstract

Gaucher disease, the most common lysosomal storage disease, is caused by mutations in the gene that encodes acid-β-glucosidase (GlcCerase). Type 1 is characterized by hepatosplenomegaly, and types 2 and 3 by early or chronic onset of severe neurological symptoms. No clear correlation exists between the ~200 GlcCerase mutations and disease severity, although homozygosity for the common mutations N370S and L444P is associated with nonneuronopathic and neuronopathic disease, respectively. We report the X-ray structure of GlcCerase at 2.0 Å resolution. The catalytic domain consists of a (β/α) 8 TIM barrel, as expected for a member of the glucosidase hydrolase A clan. The distance between the catalytic residues E235 and E340 is consistent with a catalytic mechanism of retention. N370 is located on the longest α-helix (helix 7), which has several other mutations of residues that point into the TIM barrel. Helix 7 is at the interface between the TIM barrel and a separate immunoglobulin-like domain on which L444 is located, suggesting an important regulatory or structural role for this non-catalytic domain. The structure provides the possibility of engineering improved GlcCerase for enzyme-replacement therapy, and for designing structure-based drugs aimed at restoring the activity of defective GlcCerase.

Clinical and genetic characteristics of Korean patients with Gaucher disease

“…Notably, in our study, this allele was detected only in type 1 patients and was revealed to be the most common allele (10/28 alleles, approximately 36% prevalence) in type 1 patients, suggesting that this mutation may predispose to type 1 GD, which precludes neurological involvement. A previous report suggested that based on the X-ray structure of GBA, amino acid change involving the glycine residue (G46) located in the noncatalytic domain II might have relatively minor influence on GBA structure and, therefore, catalytic activity [18]. One homozygous G46E/G46E mutation found in our study was in a female patient (case No.…”

“…Because phenylalanine (F213) and arginine (R257) residues are known to be located in α-helices 3 and 4 of the catalytic domain III of GBA [18], F213I and R257Q mutations may be associated with severe type 2 and/or 3 GD. In fact, the F213I allele was reported to be associated with a severedisease phenotype [20,21]; however, it was found in all 3 types of Korean GD patients, including 3 type 1, 1 type 2, and 4 type 3 patients.…”

“…15 and 22). The P201 residue together with the G202 residue is located near the GBA α-helix 3 region [18]. Because the G202 mutations, G202R and G202E, are known to be associated with severe phenotypes [19,22], the P201H allele seems to be a pathogenic mutation.…”

Functional analysis of 11 novel GBA alleles

“…Visual inspection of GBA three-dimensional structure 14 (PDB code 1OGS) and amino-acid substitutions were carried over using the program Coot; 15 energy minimization using the program DISCOVER3 from the InsightII program suite (Accelrys, Inc., San Diego, CA, USA). Figures were drawn using the program Chimera.…”

“…All mutated residues belong to domain III, which contains the catalytic site 14 (Figure 2). Significantly, the computational analysis revealed that, apart from p.P198S (P159S), p.G304R (G265R) and p.E365K (E326K), all mutations are directly or indirectly involved in substrate recognition (Supplementary Table S2).…”