514-45-4Relevant academic research and scientific papers
Protostadienol synthase from Aspergillus fumigatus: Functional conversion into lanosterol synthase
Kimura, Miki,Kushiro, Tetsuo,Shibuya, Masaaki,Ebizuka, Yutaka,Abe, Ikuro
experimental part, p. 899 - 902 (2011/04/16)
Oxidosqualene:protostadienol cyclase (OSPC) from the fungus Aspergillus fumigatus, catalyzes the cyclization of (3S)-2,3-oxidosqualene into protosta-17(20)Z,24-dien-3β-ol which is the precursor of the steroidal antibiotic helvolic acid. To shed light on the structure-function relationship between OSPC and oxidosqualene:lanosterol cyclase (OSLC), we constructed an OSPC mutant in which the C-terminal residues 702APPGGMR708 were replaced with 702NKSCAIS708, as in human OSLC. As a result, the mutant no longer produced the protostadienol, but instead efficiently produced a 1:1 mixture of lanosterol and parkeol. This is the first report of the functional conversion of OSPC into OSLC, which resulted in a 14-fold decrease in the Vmax/KM value, whereas the binding affinity for the substrate did not change significantly. Homology modeling suggested that stabilization of the C-20 protosteryl cation by the active-site Phe701 through cation-π interactions is important for the product outcome between protostadienol and lanosterol.
Importance of Saccharomyces cerevisiae oxidosqualene-lanosterol cyclase tyrosine 707 residue for chair-boat bicyclic ring formation and deprotonation reactions
Wu, Tung-Kung,Wang, Tsai-Ting,Chang, Cheng-Hsiang,Liu, Yuan-Ting,Shie, Wen-Shiang
scheme or table, p. 4959 - 4962 (2009/06/05)
(Chemical Equation Presented) A contact mapping strategy was applied to identify putative amino acid residues that influence the oxidosqualene- lanosterol B-ring cyclization reaction. A bicyclic intermediate with two altered deprotonation products, in conjunction with lanosterol, were isolated from the ERG7Y707X mutants, indicating that the Tyr707 residue may play a functional role in stabilizing the chair-boat bicyclic C-8 cation and the lanosteryl C-8/C-9 cation intermediates.
A putative precursor of isomalabaricane triterpenoids from lanosterol synthase mutants
Lodeiro, Silvia,Wilson, William K.,Shan, Hui,Matsuda, Seiichi P. T.
, p. 439 - 442 (2007/10/03)
Known lanosterol synthase mutants produce monocyclic or tetracyclic byproducts from oxidosqualene. We describe Erg7 Tyr510 mutants that cause partial substrate misfolding and generate a tricyclic byproduct. This novel triterpene, (13αH)-isomalabarica-14(27),17E,21-trien-3β-ol, is the likely biosynthetic precursor of isomalabaricane triterpenoids in sponges. The results suggest the facile evolution of protective triterpenoids in sessile animals.
Enzyme redesign: Two mutations cooperate to convert cycloartenol synthase into an accurate lanosterol synthase
Lodeiro, Silvia,Schulz-Gasch, Tanja,Matsuda, Seiichi P. T.
, p. 14132 - 14133 (2007/10/03)
Efforts to modify the catalytic specificity of enzymes consistently show that it is easier to broaden the substrate or product specificity of an accurate enzyme than to restrict the selectivity of one that is promiscuous. Described herein are experiments in which cycloartenol synthase was redesigned to become a highly accurate lanosterol synthase. Several single mutants have been described that modify the catalytic specificity of cycloartenol to form some lanosterol. Modeling studies were undertaken to identify combinations of mutations that cooperate to decrease the formation of products other than lanosterol. A double mutant was constructed and characterized and was shown to cyclize oxidosqualene accurately to lanosterol (99%). This catalytic change entailed both relocating polarity with a His477Asn mutation and modifying steric constraints with an Ile481Val mutation. Copyright
Steric bulk at cycloartenol synthase position 481 influences cyclization and deprotonation.
Matsuda,Darr,Hart,Herrera,McCann,Meyer,Pang,Schepmann
, p. 2261 - 2263 (2007/10/03)
Cycloartenol synthase converts oxidosqualene to the pentacyclic sterol precursor cycloartenol. An Arabidopsis thaliana cycloartenol synthase Ile481Val mutant was previously shown to produce lanosterol and parkeol in addition to its native product cycloartenol. Experiments are described here to construct Phe, Leu, Ala, and Gly mutants at position 481 and to determine their cyclization product profiles. The Phe mutant was inactive, and the Leu mutant produced cycloartenol and parkeol. The Ala and Gly mutants formed lanosterol, cycloartenol, parkeol, achilleol A, and camelliol C. Monocycles comprise most of the Gly mutant product, showing that an alternate cyclization route can be made the major pathway by a single nonpolar mutation.
