Structural insights into the catalytic mechanism of human squalene synthase

Chia I. Liu, Wen Yih Jeng, Wei Jung Chang, Min Fang Shih, Tzu Ping Ko, Andrew H J Wang

研究成果: 雜誌貢獻文章同行評審

30 引文 斯高帕斯(Scopus)

摘要

Squalene synthase (SQS) is a divalent metal-ion-dependent enzyme that catalyzes the two-step reductive 'head-to-head' condensation of two molecules of farnesyl pyrophosphate to form squalene using presqualene diphosphate (PSPP) as an intermediate. In this paper, the structures of human SQS and its mutants in complex with several substrate analogues and intermediates coordinated with Mg2+ or Mn2+ are presented, which stepwise delineate the biosynthetic pathway. Extensive study of the SQS active site has identified several critical residues that are involved in binding reduced nicotinamide dinucleotide phosphate (NADPH). Based on mutagenesis data and a locally closed (JK loop-in) structure observed in the hSQS-(F288L)-PSPP complex, an NADPH-binding model is proposed for SQS. The results identified four major steps (substrate binding, condensation, intermediate formation and translocation) of the ordered sequential mechanisms involved in the '1′-1' isoprenoid biosynthetic pathway. These new findings clarify previous hypotheses based on site-directed mutagenesis and biochemical analysis.
原文英語
頁(從 - 到)231-241
頁數11
期刊Acta Crystallographica Section D: Biological Crystallography
70
發行號2
DOIs
出版狀態已發佈 - 二月 2014

ASJC Scopus subject areas

  • 結構生物學

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