Nucleotide Sequences of Three Chalcone Reductase Genes from Alfalfa

Cloning and Functional Analysis of a Novel Aldo-Keto Reductase from Aloe arborescens

“…EF118009). The deduced amino acid sequence showed 40-67% identity to those of other AKRs from plant origin: 41.3% (132/307) identity with M. sativa PKR (chalcone reductase) (4A2), 5) 40.5% (130/307) identity with Papaver somniferum codeinone reductase (4B2), 8) 43.5% (141/307) identity with Hordeum vulgare aldehyde reductase (4C1), 9) and 66.7% (210/307) identity with Digitalis purpurea aldose reductase (4C5) 10) (Fig. 1).…”

“…A cDNA encoding a novel plant AKR was cloned and sequenced from roots of Aloe arborescens (Liliaceae) by a combination of RT-PCR using degenerate primers based on the conserved sequences of PKRs (chalcone reductases) from legume plants (AKR4A1-4A4) including Medicago sativa (Fabaceae), 5) and cDNA library screening by oligonucleotide hybridization. A full-length cDNA contained a 924-bp open reading frame encoding a Mr 34199 protein with 307 amino acids (the nucleotide sequence has been deposited in the EMBL/DDBJ/GenBank TM data bases under accession no.…”

“…Total RNA was extracted by the acid guanidium thiocyanatephenol-chloroform method, and reverse-transcribed using Reverscript (Wako) and oligo dT primer according to the manufacturer's protocol. The obtained cDNA mixture was used as a template for the PCR reactions with degenerate oligonucleotide primers based on the conserved sequences of known PKRs (chalcone reductases) [4][5][6][7] ; S1ϭ5Ј- (Fig. 1).…”

“…[4][5][6][7] Although the buried nature of the CHS active-site precludes PKR from accessing the CHS-enzyme-bound polyketide intermediate, PKR is thought to reduce a carbonyl group of a linear polyketide intermediate (or a non-aromatized 1,3,5-cyclohexatrione intermediate) prior to formation of the aromatic ring system. 16,17) To further study the plant PKR enzymes, we carried out cloning of PKRs from a medicinal plant Aloe arborescens (Liliaceae) that produces considerable amount of the "reduced" polyketides including anthrones and anthraquinones.…”

“…Within the plant AKRs, aldose reductase, 3) polyketide reductase (PKR) (chalcone reductase), [4][5][6][7] alkaloid reductase (codeinone reductase), 8) and several plant oxidoreductases of poorly defined function [9][10][11][12][13][14] constitute the unique AKR4 family. Crystal structures of the first AKR4 members, Hordeum vulgare aldose reductase (4C1) 15) and Medicago sativa PKR (chalcone reductase) (4A2) 16) have recently been reported.…”