Efficient Hydrolysis of Gluten-Derived Celiac Disease-Triggering Immunogenic Peptides by a Bacterial Serine Protease from Burkholderia gladioli

Abstract

Celiac disease is an autoimmune disorder triggered by toxic peptides derived from incompletely digested glutens in the stomach. Peptidases that can digest the toxic peptides may formulate an oral enzyme therapy to improve the patients’ health condition. Bga1903 is a serine endopeptidase secreted by Burkholderia gladioli. The preproprotein of Bga1903 consists of an N-terminal signal peptide, a propeptide region, and an enzymatic domain that belongs to the S8 subfamily. Bga1903 could be secreted into the culture medium when it was expressed in E. coli. The purified Bga1903 is capable of hydrolyzing the gluten-derived toxic peptides, such as the 33- and 26-mer peptides, with the preference for the peptide bonds at the carbonyl site of glutamine (P1 position). The kinetic assay of Bga1903 toward the chromogenic substrate Z-HPQ-pNA at 37 °C, pH 7.0, suggests that the values of Km and kcat are 0.44 ± 0.1 mM and 17.8 ± 0.4 s−1, respectively. The addition of Bga1903 in the wort during the fermentation step of beer could help in making gluten-free beer. In summary, Bga1903 is usable to reduce the gluten content in processed foods and represents a good candidate for protein engineering/modification aimed to efficiently digest the gluten at the gastric condition.

Specificity Enhancement of Glutenase Bga1903 toward Celiac Disease-Eliciting Pro-Immunogenic Peptides via Active-Site Modification

“…Bga1903 preferentially cut the bond at the carbonyl side of glutamine when it acted on the 26- and 33-mer peptides; nonetheless, it showed rather relaxed selectivity at the P1 residue, with a preference for lysine, followed by phenylalanine, leucine, and glutamine when bovine serum albumin served as the substrate [ 21 ]. These observations imply that elevating the catalytic specificity of Bga1903 toward pro-immunogenic peptides could be potentially achieved through strategic alterations of subsite S1 within the peptidyl-binding pocket.…”

“…In previous studies, we identified a serine peptidase, named Bga1903, with gliadin hydrolytic activity from Burkholderia gladioli [ 21 ]. Bga1903 has the capability of being secreted into the culture medium by Escherichia coli BL21(DE3).…”

Gut microbiota predicts the diagnosis of celiac disease in Saudi children

“…Burkholderiales bacterium 1-1-47 is an unclassified bacterium belonging to the order Burkholderiales , class Betaproteobacteria and phylum Proteobacteria [ 23 ]. Several Burkholderiales species and Burkholderia gladioli in particular have been reported to produce peptidases that hydrolyze gluten peptides, with the potential to reduce the gluten content of food[ 24 ]. Accordingly, reports of decreased abundance of both Bacteroides intestinalis and Burkholderiales bacterium 1-1-47 in samples from children with CeD[ 13 ], indicate a potential protective role against the effects of gluten-containing grains.…”

Hydrolysis of Gluten-Derived Celiac Disease-Triggering Peptides across a Broad pH Range by RmuAP1: A Novel Aspartic Peptidase Isolated from Rhodotorula mucilaginosa

“…To obtain peptidases that could be beneficial for treating CeD, a serine peptidase, called Bga1903, from Burkholderia gladioli was recently characterized in our laboratory. 25 Bga1903 belongs to the S8 peptidase family according to MEROPS classification 26 and exhibits notable activity in breaking down the 33-and 26-mer peptides, with a particular preference for glutamine located at the P1 position. Active-site modifications based on the crystal structure of Bga1903 further enhanced the proteolytic activity of Bga1903 toward GIPs.…”