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Key amino acid residues required for aryl migration catalysed by the cytochrome P450 2-hydroxyisoflavanone synthase.
Plant J. 2002 Sep; 31(5):555-64.PJ

Abstract

Isoflavonoids are distributed predominantly in leguminous plants, and play pivotal roles in the interaction of host plants with biological environments. Isoflavones in the diet also have beneficial effects on human health as phytoestrogens. The isoflavonoid skeleton is constructed by the CYP93C subfamily of cytochrome P450s in plant cells. The reaction consists of hydroxylation of the flavanone molecule at C-2 and an intramolecular 1,2-aryl migration from C-2 to C-3 to yield 2-hydroxyisoflavanone. In this study, with the aid of alignment of amino acid sequences of CYP93 family P450s and a computer-generated putative stereo structure of the protein, candidates for key amino acid residues in CYP93C2 responsible for the unique aryl migration in 2-hydroxyisoflavanone synthase reaction were identified. Microsomes of recombinant yeast cells expressing mutant proteins of CYP93C2 were prepared, and their catalytic activities tested. The reaction with the mutant in which Ser 310 in the centre of the I-helix was converted to Thr yielded increased formation of 3-hydroxyflavanone, a by-product of the 2-hydroxyisoflavanone synthase reaction, in addition to the major isoflavonoid product. More dramatically, the mutant in which Lys 375 in the end of beta-sheet 1-4 was replaced with Thr produced only 3-hydroxyflavanone and did not yield the isoflavonoid any longer. The roles of these amino acid residues in the catalysis and evolution of isoflavonoid biosynthesis are discussed.

Authors+Show Affiliations

Department of Applied Biological Sciences, Nihon University, Fujisawa, Kanagawa 252-8510, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12207646

Citation

Sawada, Yuji, et al. "Key Amino Acid Residues Required for Aryl Migration Catalysed By the Cytochrome P450 2-hydroxyisoflavanone Synthase." The Plant Journal : for Cell and Molecular Biology, vol. 31, no. 5, 2002, pp. 555-64.
Sawada Y, Kinoshita K, Akashi T, et al. Key amino acid residues required for aryl migration catalysed by the cytochrome P450 2-hydroxyisoflavanone synthase. Plant J. 2002;31(5):555-64.
Sawada, Y., Kinoshita, K., Akashi, T., Aoki, T., & Ayabe, S. (2002). Key amino acid residues required for aryl migration catalysed by the cytochrome P450 2-hydroxyisoflavanone synthase. The Plant Journal : for Cell and Molecular Biology, 31(5), 555-64.
Sawada Y, et al. Key Amino Acid Residues Required for Aryl Migration Catalysed By the Cytochrome P450 2-hydroxyisoflavanone Synthase. Plant J. 2002;31(5):555-64. PubMed PMID: 12207646.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Key amino acid residues required for aryl migration catalysed by the cytochrome P450 2-hydroxyisoflavanone synthase. AU - Sawada,Yuji, AU - Kinoshita,Kengo, AU - Akashi,Tomoyoshi, AU - Aoki,Toshio, AU - Ayabe,Shin-Ichi, PY - 2002/9/5/pubmed PY - 2002/12/10/medline PY - 2002/9/5/entrez SP - 555 EP - 64 JF - The Plant journal : for cell and molecular biology JO - Plant J. VL - 31 IS - 5 N2 - Isoflavonoids are distributed predominantly in leguminous plants, and play pivotal roles in the interaction of host plants with biological environments. Isoflavones in the diet also have beneficial effects on human health as phytoestrogens. The isoflavonoid skeleton is constructed by the CYP93C subfamily of cytochrome P450s in plant cells. The reaction consists of hydroxylation of the flavanone molecule at C-2 and an intramolecular 1,2-aryl migration from C-2 to C-3 to yield 2-hydroxyisoflavanone. In this study, with the aid of alignment of amino acid sequences of CYP93 family P450s and a computer-generated putative stereo structure of the protein, candidates for key amino acid residues in CYP93C2 responsible for the unique aryl migration in 2-hydroxyisoflavanone synthase reaction were identified. Microsomes of recombinant yeast cells expressing mutant proteins of CYP93C2 were prepared, and their catalytic activities tested. The reaction with the mutant in which Ser 310 in the centre of the I-helix was converted to Thr yielded increased formation of 3-hydroxyflavanone, a by-product of the 2-hydroxyisoflavanone synthase reaction, in addition to the major isoflavonoid product. More dramatically, the mutant in which Lys 375 in the end of beta-sheet 1-4 was replaced with Thr produced only 3-hydroxyflavanone and did not yield the isoflavonoid any longer. The roles of these amino acid residues in the catalysis and evolution of isoflavonoid biosynthesis are discussed. SN - 0960-7412 UR - https://www.unboundmedicine.com/medline/citation/12207646/Key_amino_acid_residues_required_for_aryl_migration_catalysed_by_the_cytochrome_P450_2_hydroxyisoflavanone_synthase_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0960-7412&date=2002&volume=31&issue=5&spage=555 DB - PRIME DP - Unbound Medicine ER -