Molecules, Vol. 26, Pages 7249: Structural Analysis of Saccharomyces cerevisiae Dihydroorotase Reveals Molecular Insights into the Tetramerization Mechanism

Molecules, Vol. 26, Pages 7249: Structural Analysis of Saccharomyces cerevisiae Dihydroorotase Reveals Molecular Insights into the Tetramerization Mechanism Molecules doi: 10.3390/molecules26237249 Authors: Hong-Hsiang Guan Yen-Hua Huang En-Shyh Lin Chun-Jung Chen Cheng-Yang Huang Dihydroorotase (DHOase), a dimetalloenzyme containing a carbamylated lysine within the active site, is a member of the cyclic amidohydrolase family, which also includes allantoinase (ALLase), dihydropyrimidinase (DHPase), hydantoinase, and imidase. Unlike most known cyclic amidohydrolases, which are tetrameric, DHOase exists as a monomer or dimer. Here, we report and analyze two crystal structures of the eukaryotic Saccharomyces cerevisiae DHOase (ScDHOase) complexed with malate. The structures of different DHOases were also compared. An asymmetric unit of these crystals contained four crystallographically independent ScDHOase monomers. ScDHOase shares structural similarity with Escherichia coli DHOase (EcDHOase). Unlike EcDHOase, ScDHOase can form tetramers, both in the crystalline state and in solution. In addition, the subunit-interacting residues of ScDHOase for dimerization and tetramerization are significantly different from those of other DHOases. The tetramerization pattern of ScDHOase is also different from those of DHPase and ALLase. Based on sequence analysis and structural evidence, we identify two unique helices (α6 and α10) and a loop (loop 7...
Source: Molecules - Category: Chemistry Authors: Tags: Article Source Type: research