標題: Combined Experimental and Theoretical Study of Long-Range Interactions Modulating Dimerization and Activity of Yeast Geranylgeranyl Diphosphate Synthase
作者: Lo, Chia-Hsiang
Chang, Ying-Hsuan
Wright, Jon D.
Chen, Shih-Hsun
Kan, Daphne
Lim, Carmay
Liang, Po-Huang
生物科技學系
Department of Biological Science and Technology
公開日期: 25-Mar-2009
摘要: We present here how two amino acid residues in the first helix distal from the main dimer interface modulate the dimerization and activity of a geranylgeranyl diphosphate synthase (GGPPs). The enzyme catalyzes condensation of farnesyl diphosphate and isopentenyl diphosphate to generate a C(20) product as a precursor for chlorophylls, carotenoids, and geranylgeranylated proteins. The 3D structure of GGPPs from Saccharomyces cerevisiae reveals an unique positioning of the N-terminal helix A, which protrudes into the other subunit and stabilizes dimerization, although it is far from the main dimer interface. Through a series of mutants that were characterized by analytic ultracentrifugation (AUC), the replacement of L8 and 19 at this helix with Gly was found sufficient to disrupt the dimer into a monomer, leading to at least 10(3)-fold reduction in activity. Molecular dynamics simulations and free energy decomposition analyses revealed the possible effects of the mutations on the protein structures and several critical interactions for maintaining dimerization. Further site-directed mutagenesis and AUC studies elucidated the molecular mechanism for modulating dimerization and activity by long-range interactions.
URI: http://dx.doi.org/10.1021/ja808699c
http://hdl.handle.net/11536/7465
ISSN: 0002-7863
DOI: 10.1021/ja808699c
期刊: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume: 131
Issue: 11
起始頁: 4051
結束頁: 4062
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