Fighting Celiac Disease: Improvement of pH Stability of Cathepsin L In Vitro by Computational Design

• Published in: International journal of molecular sciences Vol. 24; no. 15; p. 12369
• Main Authors: Chugunov, Anton O, Dvoryakova, Elena A, Dyuzheva, Maria A, Simonyan, Tatyana R, Tereshchenkova, Valeria F, Filippova, Irina Yu, Efremov, Roman G, Elpidina, Elena N
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-08-2023; MDPI
• Subjects: acid stability; Acidification; cathepsin L; Cathepsins; Celiac disease; Disease susceptibility; Enzymes; Glutamine; Gluten; gluten intolerance; glutenase; Grain; Hydrogen-ion concentration; Immune response; Molecular dynamics; Peptides; post-glutamine cleaving peptidase; Proline; Proteins; Simulation; Russia; glutenase; gluten intolerance; celiac disease; Tribolium castaneum; post-glutamine cleaving peptidase; acid stability; cathepsin L; molecular dynamics
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms241512369

Roughly 1% of the global population is susceptible to celiac disease (CD)-inheritable autoimmune inflammation of the small intestine caused by intolerance to gliadin proteins present in wheat, rye, and barley grains, and called gluten in wheat. Classical treatment is a life-long gluten-free diet, which is constraining and costly. An alternative approach is based upon the development and oral reception of effective peptidases that degrade in the stomach immunogenic proline- and glutamine-rich gliadin peptides, which are the cause of the severe reaction in the intestine. In previous research, we have established that the major digestive peptidase of an insect
-cathepsin L-hydrolyzes immunogenic prolamins after Gln residues but is unstable in the extremely acidic environment (pH 2-4) of the human stomach and cannot be used as a digestive aid. In this work, using molecular dynamics simulations, we discover the probable cause of the pH instability of cathepsin L-loss of the catalytically competent rotameric state of one of the active site residues, His 275. To "fix" the correct orientation of this residue, we designed a V277A mutant variant, which extends the range of stability of the peptidase in the acidic environment while retaining most of its activity. We suggest this protein as a lead glutenase for the development of oral medical preparation that fights CD and gluten intolerance in susceptible people.