TY - JOUR
T1 - Protostadienol synthase from Aspergillus fumigatus
T2 - Functional conversion into lanosterol synthase
AU - Kimura, Miki
AU - Kushiro, Tetsuo
AU - Shibuya, Masaaki
AU - Ebizuka, Yutaka
AU - Abe, Ikuro
N1 - Funding Information:
We thank Professor Tung-Kung Wu (National Chiao Tung University, Republic of China) for the gift of the authentic samples of parkeol and protosta-13(17),24-dien-3β-ol. This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan , and by Grant-in-Aids from The Yamada Science Foundation , and the Astellas Foundation for Research on Metabolic Disorders, Japan .
Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2010/1/1
Y1 - 2010/1/1
N2 - 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.
AB - 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.
KW - Helvolic acid
KW - Lanosterol synthase
KW - Oxidosqualene cyclase
KW - Protostadienol synthase
KW - Steroidal antibiotics
UR - http://www.scopus.com/inward/record.url?scp=72949113214&partnerID=8YFLogxK
U2 - 10.1016/j.bbrc.2009.11.160
DO - 10.1016/j.bbrc.2009.11.160
M3 - Article
C2 - 19951700
AN - SCOPUS:72949113214
VL - 391
SP - 899
EP - 902
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 1
ER -