Information on EC 1.14.15.9 - spheroidene monooxygenase

CrtA

4 entries

2',2'-dihydroxy-2-oxospirilloxanthin = 2,2'-dioxospirilloxanthin + H2O

(3c), spontaneous

-

2'-hydroxy-2-oxospirilloxanthin + reduced ferredoxin [iron-sulfur] cluster + O2 + 2 H+ = 2',2'-dihydroxy-2-oxospirilloxanthin + oxidized ferredoxin [iron-sulfur] cluster + H2O

(3b)

-

2,2-dihydroxyspheroidene = spheroiden-2-one + H2O

(1c), spontaneous

-

2,2-dihydroxyspirilloxanthin = 2-oxospirilloxanthin + H2O

(2c), spontaneous

-

2-hydroxyspheroidene + 2 reduced ferredoxin [iron-sulfur] cluster + O2 + 2 H+ = 2,2-dihydroxyspheroidene + 2 oxidized ferredoxin [iron-sulfur] cluster + H2O

(1b)

-

2-hydroxyspirilloxanthin + 2 reduced ferredoxin [iron-sulfur] cluster + O2 + 2 H+ = 2,2-dihydroxyspirilloxanthin + 2 oxidized ferredoxin [iron-sulfur] cluster + H2O

(2b)

-

2-oxospirilloxanthin + 2 reduced ferredoxin [iron-sulfur] cluster + O2 + 2 H+ = 2'-hydroxy-2-oxospirilloxanthin + 2 oxidized ferredoxin [iron-sulfur] cluster + H2O

(3a)

-

2-oxospirilloxanthin + 4 reduced ferredoxin [iron-sulfur] cluster + 2 O2 = 2,2'-dioxospirilloxanthin + 4 oxidized ferredoxin [iron-sulfur] cluster + 3 H2O

(3)

-

spheroidene + 2 reduced ferredoxin [iron-sulfur] cluster + O2 + 2 H+ = 2-hydroxyspheroidene + 2 oxidized ferredoxin [iron-sulfur] cluster + H2O

(1a)

-

spheroidene + 4 reduced ferredoxin [iron-sulfur] cluster + 2 O2 = spheroiden-2-one + 4 oxidized ferredoxin [iron-sulfur] cluster + 3 H2O

Biosynthesis of secondary metabolites, Carotenoid biosynthesis

spirilloxanthin + 2 reduced ferredoxin [iron-sulfur] cluster + O2 + 2 H+ = 2-hydroxyspirilloxanthin + 2 oxidized ferredoxin [iron-sulfur] cluster + H2O

(2a)

-

spirilloxanthin + 4 reduced ferredoxin [iron-sulfur] cluster + 2 O2 = 2-oxospirilloxanthin + 4 oxidized ferredoxin [iron-sulfur] cluster + 3 H2O

(2)

-

KEGG

MetaCyc

spheroidene and spheroidenone biosynthesis, spirilloxanthin and 2,2'-diketo-spirilloxanthin biosynthesis

spheroidene,reduced-ferredoxin:oxygen oxidoreductase (spheroiden-2-one-forming)

The enzyme is involved in spheroidenone biosynthesis and in 2,2'-dioxospirilloxanthin biosynthesis. The enzyme from Rhodobacter sphaeroides contains heme at its active site [1].

1'-hydroxy-1-demethylspheroidene + reduced ferredoxin + O2

1'-hydroxy-1-demethylspheroiden-2-one + oxidized ferredoxin + H2O

1'-hydroxyspheroidene + reduced ferredoxin + O2

1'-hydroxyspheroiden-2-one + oxidized ferredoxin + H2O

1,1'-dihydroxy-3,4-didehydrolycopene + 2 reduced ferredoxin + 2 O2

2,2'-dioxo-1,1'-dihydroxy-3,4-didehydrolycopene + 2 oxidized ferredoxin + 2 H2O

-

711281

-

?

1-hydroxy-3,4-didehydrolycopene + reduced ferredoxin + O2

2-oxo-1-hydroxy-3,4-didehydrolycopene + oxidized ferredoxin + H2O

-

711281

-

?

2-hydroxyspheroidene + reduced ferredoxin + O2

spheroiden-2-one + oxidized ferredoxin + H2O

3,4,3',4'-tetradehydrolycopene + reduced ferredoxin + O2

1,1'-dihydroxy-3,4,3',4'-tetradehydrolycopen-2-one + oxidized ferredoxin + H2O

-

-

?

3,4,3',4'-tetradehydrolycopene + reduced ferredoxin + O2

1-hydroxy-3,4,3',4'-tetradehydrolycopen-2-one + oxidized ferredoxin + H2O

-

-

?

3,4-didehydrolycopene + reduced ferredoxin + O2

1-hydroxy-3,4-didehydrolycopen-2-one + oxidized ferredoxin + H2O

-

-

?

spheroidene + reduced ferredoxin + O2

spheroiden-2-one + oxidized ferredoxin + H2O

spheroidene + reduced ferredoxin + O2

spheroidenone + oxidized ferredoxin + H2O

-

711028

-

?

spirilloxanthin + 2 reduced ferredoxin + 2 O2

2,2'-dioxosprilloxanthin + 2 oxidized ferredoxin + 2 H2O

spirilloxanthin + reduced ferredoxin + O2

2-oxospirilloxanthin + oxidized ferredoxin + H2O

spheroidene + reduced ferredoxin + O2

spheroiden-2-one + oxidized ferredoxin + H2O

Rhodovulum sulfidophilum

-

conversion rate: 36%

711804

-

?

heme

-

CrtA has a 5-coordinated heme at its active site

0.0101 - 0.0155

1'-hydroxyspheroidene

0.007 - 0.0191

spheroidene

0.009 - 0.0181

spirilloxanthin

4 entries

7.8

28

-

711281, 711732, 712334, 713039

-

-

-

Rhodovulum sulfidophilum

-

710953, 711804

-

-

711028, 711281

-

malfunction

physiological function

-

the enzyme is involved in spheroidene biosynthesis pathway and spirilloxanthin biosynthesis pathway. Methylated carotenoids, such as spheroidene and spirilloxanthin, function as accessory pigments in the light-harvesting and reaction-center complexes of purple bacteria

711028

32000

-

x * 32000, SDS-PAGE

711281

65000

-

x * 65000, calculated from sequence

713039

?

-

-

-

713039

expression in Escherichia coli

expression in Escherichia coli. Coexpression of CrtA with acyclic C40 carotenoid pathways can introduce a keto group at the C(2,2') position of unnatural substrates that do not exhibit a C(3,4) double bond. The complete conversion of tetradehydrolycopene to phillipsiaxanthin observed suggests it is a favorable substrate for CrtA activity when compared to the incomplete conversion of lycopene to lycopene-2-one in the presence of CrtA