Structure, Assembly, and Mechanism of a PLP-Dependent Dodecameric l-Aspartate β-Decarboxylase

Hui Ju Chen, Tzu Ping Ko, Chia Yin Lee, Nai Chen Wang, Andrew H.J. Wang

研究成果: 雜誌貢獻文章同行評審

22 引文 斯高帕斯(Scopus)

摘要

The type-I PLP enzyme l-aspartate β-decarboxylase converts aspartate to alanine and CO2. Similar to the homodimeric aminotransferases, its protein subunit comprises a large and a small domain, of 410 and 120 residues, respectively. The crystal structure reveals a dodecamer made of six identical dimers arranged in a truncated tetrahedron whose assembly involves tetramer and hexamer as intermediates. The additional helical motifs I and II participate in the oligomer formation. Triple mutations of S67R/Y68R/M69R or S67E/Y68E/M69E in motif I produced an inactive dimer. The PLP is bound covalently to Lys315 in the active site, while its phosphate group interacts with a neighboring Tyr134. Removal of the bulky side chain of Arg37, which overhangs the PLP group, improved the substrate affinity. Mutations in flexible regions produced the more active K17A and the completely inactive R487A. The structure also suggests that substrate binding triggers conformational changes essential for catalyzing the reaction.

原文英語
頁(從 - 到)517-529
頁數13
期刊Structure
17
發行號4
DOIs
出版狀態已發佈 - 4月 15 2009
對外發佈

ASJC Scopus subject areas

  • 結構生物學
  • 分子生物學

指紋

深入研究「Structure, Assembly, and Mechanism of a PLP-Dependent Dodecameric l-Aspartate β-Decarboxylase」主題。共同形成了獨特的指紋。

引用此