Heterogeneity of active sites in recombinant betaine aldehyde dehydrogenase is modulated by potassium
| Autor: | Ciria G. Figueroa-Soto, Aldo A. Arvizu-Flores, Jesús A. Rosas-Rodríguez, Aurora Stephens‐Camacho, César Muñoz-Bacasehua, José G. Soñanez-Organis, Elisa M. Valenzuela-Soto |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Protein Conformation
Sus scrofa Betaine-Aldehyde Dehydrogenase Kidney 010402 general chemistry 01 natural sciences Cofactor chemistry.chemical_compound Betaine Structural Biology Catalytic Domain Animals Amino Acid Sequence Molecular Biology chemistry.chemical_classification biology Chemistry 010401 analytical chemistry Temperature Active site Isothermal titration calorimetry Hydrogen-Ion Concentration 0104 chemical sciences NAD binding Enzyme Biochemistry Potassium biology.protein Betaine-aldehyde dehydrogenase NAD+ kinase Sequence Alignment |
| Zdroj: | Journal of Molecular Recognition. 33 |
| ISSN: | 1099-1352 0952-3499 |
| DOI: | 10.1002/jmr.2869 |
| Popis: | Betaine aldehyde dehydrogenase (BADH EC 1.2.1.8) catalyzes the irreversible oxidation of betaine aldehyde to glycine betaine using NAD+ as a coenzyme. Porcine kidney BADH (pkBADH) follows a bi-bi ordered mechanism in which NAD+ binds to the enzyme before the aldehyde. Previous studies showed that NAD+ induces complex and unusual conformational changes on pkBADH and that potassium is required to maintain its quaternary structure. The aim of this work was to analyze the structural changes in pkBADH caused by NAD+ binding and the role played by potassium in those changes. The pkBADH cDNA was cloned and overexpressed in Escherichia coli, and the protein was purified by affinity chromatography using a chitin matrix. The pkBADH/NAD+ interaction was analyzed by circular dichroism (CD) and by isothermal titration calorimetry (ITC) by titrating the enzyme with NAD+ . The cDNA has an open reading frame of 1485 bp and encodes a protein of 494 amino acids, with a predicted molecular mass of 53.9 kDa. CD data showed that the binding of NAD+ to the enzyme caused changes in its secondary structure, whereas the presence of K+ helps maintain its α-helix content. K+ increased the thermal stability of the pkBADH-NAD+ complex by 5.3°C. ITC data showed that NAD+ binding occurs with different association constants for each active site between 37.5 and 8.6 μM. All the results support previous data in which the enzyme incubation with NAD+ provoked changes in reactivity, which is an indication of slow conformational rearrangements of the active site. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text