Single-particle analysis of urea amidolyase reveals its molecular mechanism
Autor: | Liang Peng, Jing Zhao, Ying Liu, Yuhua Huang, Yi Wu, Bin Yuan, Song Xiang, Xinxing Zheng, Li Zhu, Yuerong Zhou, Bin Cheng |
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Rok vydání: | 2019 |
Předmět: |
Biotin carboxylase
Protein Conformation Biotin carboxyl carrier protein Biochemistry 03 medical and health sciences chemistry.chemical_compound Fatty Acid Synthase Type II Transferase Humans Phosphofructokinase 2 Carbon-Nitrogen Ligases Molecular Biology Urea carboxylase 030304 developmental biology Kluyveromyces lactis 0303 health sciences biology Chemistry 030302 biochemistry & molecular biology biology.organism_classification Single Molecule Imaging Structural biology biology.protein Urea Biocatalysis Protein Structure Reports Acetyl-CoA Carboxylase |
Zdroj: | Protein Sci |
ISSN: | 1469-896X |
Popis: | Urea amidolyase (UA), a bifunctional enzyme that is widely distributed in bacteria, fungi, algae, and plants, plays a pivotal role in the recycling of nitrogen in the biosphere. Its substrate urea is ultimately converted to ammonium, via successive catalysis at the C-terminal urea carboxylase (UC) domain and followed by the N-terminal allophanate hydrolyse (AH) domain. Although our previous studies have shown that Kluyveromyces lactis UA (KlUA) functions efficiently as a homodimer, the architecture of the full-length enzyme remains unresolved. Thus how the biotin carboxyl carrier protein (BCCP) domain is transferred within the UC domain remains unclear. Here we report the structures of full-length KlUA in its homodimer form in three different functional states by negatively-stained single-particle electron microscopy. We report here that the ADP-bound structure with or without urea shows two possible locations of BCCP with preferred asymmetry, and that when BCCP is attached to the carboxyl transferase domain of one monomer, it is attached to the biotin carboxylase domain in the second domain. Based on this observation, we propose a BCCP-swinging model for biotin-dependent carboxylation mechanism of this enzyme. |
Databáze: | OpenAIRE |
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