Functional Impact of the N-terminal Arm of Proline Dehydrogenase from Thermus thermophilus

Autor: Mieke M. E. Huijbers, Ilona van Alen, Jenny W. Wu, Arjan Barendregt, Albert J. R. Heck, Willem J. H. van Berkel
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Molecules, Vol 23, Iss 1, p 184 (2018)
Druh dokumentu: article
ISSN: 1420-3049
DOI: 10.3390/molecules23010184
Popis: Proline dehydrogenase (ProDH) is a ubiquitous flavoenzyme that catalyzes the oxidation of proline to Δ1-pyrroline-5-carboxylate. Thermus thermophilus ProDH (TtProDH) contains in addition to its flavin-binding domain an N-terminal arm, consisting of helices αA, αB, and αC. Here, we report the biochemical properties of the helical arm truncated TtProDH variants ΔA, ΔAB, and ΔABC, produced with maltose-binding protein as solubility tag. All three truncated variants show similar spectral properties as TtProDH, indicative of a conserved flavin-binding pocket. ΔA and ΔAB are highly active tetramers that rapidly react with the suicide inhibitor N-propargylglycine. Removal of the entire N-terminal arm (ΔABC) results in barely active dimers that are incapable of forming a flavin adduct with N-propargylglycine. Characterization of V32D, Y35F, and V36D variants of ΔAB established that a hydrophobic patch between helix αC and helix α8 is critical for TtProDH catalysis and tetramer stabilization.
Databáze: Directory of Open Access Journals
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