Two BAHD Acyltransferases Catalyze the Last Step in the Shikonin/Alkannin Biosynthetic Pathway.
Plant Physiol
; 184(2): 753-761, 2020 10.
Article
em En
| MEDLINE
| ID: mdl-32727911
ABSTRACT
Several Boraginaceae plants produce biologically active red naphthoquinone pigments, derivatives of the enantiomers shikonin and alkannin, which vary in acyl groups on their side chains. Compositions of shikonin/alkannin derivatives vary in plant species, but the mechanisms generating the diversity of shikonin/alkannin derivatives are largely unknown. This study describes the identification and characterization of two BAHD acyltransferases, shikonin O-acyltransferase (LeSAT1) and alkannin O-acyltransferase (LeAAT1), from Lithospermum erythrorhizon, a medicinal plant in the family Boraginaceae that primarily produces the shikonin/alkannin derivatives acetylshikonin and ß-hydroxyisovalerylshikonin. Enzyme assays using Escherichia coli showed that the acylation activity of LeSAT1 was specific to shikonin, whereas the acylation activity of LeAAT1 was specific to alkannin. Both enzymes recognized acetyl-CoA, isobutyryl-CoA, and isovaleryl-CoA as acyl donors to produce their corresponding shikonin/alkannin derivatives, with both enzymes showing the highest activity for acetyl-CoA. These findings were consistent with the composition of shikonin/alkannin derivatives in intact L erythrorhizon plants and cell cultures. Genes encoding both enzymes were preferentially expressed in the roots and cell cultures in the dark in pigment production medium M9, conditions associated with shikonin/alkannin production. These results indicated that LeSAT1 and LeAAT1 are enantiomer-specific acyltransferases that generate various shikonin/alkannin derivatives.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Aciltransferases
/
Naftoquinonas
/
Lithospermum
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Plant Physiol
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Japão