Funke, Franziska Jasmin and Schlee, Sandra and Bento, Isabel and Bourenkov, Gleb and Sterner, Reinhard and Wilmanns, Matthias (2025) Activity Regulation of a Glutamine Amidotransferase Bienzyme Complex by Substrate-Induced Subunit Interface Expansion. ACS CATALYSIS, 15 (5). pp. 4359-4373. ISSN 2155-5435
Full text not available from this repository. (Request a copy)Abstract
Glutamine amidotransferases are multienzyme machineries in which reactive ammonia is generated by a glutaminase and then transferred through a sequestered protein tunnel to a synthase active site for incorporation into diverse metabolites. To avoid wasteful metabolite consumption, there is a requirement for synchronized catalysis, but any generally applicable mechanistic insight is still lacking. As synthase activity depends on glutamine turnover, we investigated possible mechanisms controlling glutaminase catalysis using aminodeoxychorismate synthase involved in folate biosynthesis as a model. By analyzing this system in distinct states of catalysis, we found that incubation with glutamine leads to a subunit interface expansion by one-third of its original area. These changes completely enclose the glutaminase active site for sequestered catalysis and the subsequent transport of volatile ammonia to the synthase active site. In view of similar rearrangements in other glutamine amidotransferases, our observations may provide a general mechanism for the catalysis synchronization of this multienzyme family.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | COLI AMINODEOXYCHORISMATE SYNTHASE; CARBAMOYL-PHOSPHATE SYNTHETASE; PARA-AMINOBENZOATE SYNTHESIS; ESCHERICHIA-COLI; PROTEIN INTERACTIONS; CHORISMATE; AMMONIA; CONSERVATION; MUTATIONS; MECHANISM; multienzyme complex; nitrogen-containingmetabolites; ammonia utilization in catalysis; substrate/productsequestration; enzyme product/substrate tunnel; active site interface expansion |
| Subjects: | 500 Science > 540 Chemistry & allied sciences 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie > Prof. Dr. Reinhard Sterner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 13 Aug 2026 04:29 |
| Last Modified: | 13 Aug 2026 04:29 |
| URI: | https://pred.uni-regensburg.de/id/eprint/66446 |
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