Cloned (Comment) | Organism |
---|---|
gene crtQa, expressionin Escherichia coli, gene crtQb, expression of CrtQB in Escherichia coli strain JM101 | Nostoc sp. |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
7,9,9'-tricis-neurosporene + a quinone | Nostoc sp. | catalyzed by zeta-carotene desaturase CrtQa, very poorly by CrtQb | 7,9,7',9'-tetracis-lycopene + a quinol | - |
? | |
7,9,9'-tricis-neurosporene + a quinone | Nostoc sp. PCC 7120 | catalyzed by zeta-carotene desaturase CrtQa, very poorly by CrtQb | 7,9,7',9'-tetracis-lycopene + a quinol | - |
? | |
9,9'-dicis-zeta-carotene + a quinone | Nostoc sp. | catalyzed by zeta-carotene desaturases CrtQa and CrtQb | 7,9,9'-tricis-neurosporene + a quinol | - |
? | |
9,9'-dicis-zeta-carotene + a quinone | Nostoc sp. PCC 7120 | catalyzed by zeta-carotene desaturases CrtQa and CrtQb | 7,9,9'-tricis-neurosporene + a quinol | - |
? | |
additional information | Nostoc sp. | strain PCC 7120 contains two completely unrelated zeta-carotene desaturases CrtQa and CrtQb, which differ in their preferred utilization of zeta-carotene Z isomers. CrtQa converts zeta-carotene isomers that are poorly metabolized by CrtQb and CrtQa still possesses the Z to E isomerase function of the ancestral desaturase CrtI. CrtQb is an enzyme with one molecule of tightly bound FAD and acts as a dehydrogenase transferring hydrogen to oxidized plastoquinone. CrtQb yields only trace amounts of 7,9-Z neurosporene and 7,9,7',9'-Z lycopene | ? | - |
? | |
additional information | Nostoc sp. PCC 7120 | strain PCC 7120 contains two completely unrelated zeta-carotene desaturases CrtQa and CrtQb, which differ in their preferred utilization of zeta-carotene Z isomers. CrtQa converts zeta-carotene isomers that are poorly metabolized by CrtQb and CrtQa still possesses the Z to E isomerase function of the ancestral desaturase CrtI. CrtQb is an enzyme with one molecule of tightly bound FAD and acts as a dehydrogenase transferring hydrogen to oxidized plastoquinone. CrtQb yields only trace amounts of 7,9-Z neurosporene and 7,9,7',9'-Z lycopene | ? | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Nostoc sp. | - |
contains two completely unrelated zeta-carotene desaturases CrtQa and CrtQb, encoded by genes crtQa and crtQb | - |
Nostoc sp. PCC 7120 | - |
contains two completely unrelated zeta-carotene desaturases CrtQa and CrtQb, encoded by genes crtQa and crtQb | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
7,9,9'-tricis-neurosporene + a quinone | catalyzed by zeta-carotene desaturase CrtQa, very poorly by CrtQb | Nostoc sp. | 7,9,7',9'-tetracis-lycopene + a quinol | - |
? | |
7,9,9'-tricis-neurosporene + a quinone | catalyzed by zeta-carotene desaturase CrtQa, very poorly by CrtQb | Nostoc sp. PCC 7120 | 7,9,7',9'-tetracis-lycopene + a quinol | - |
? | |
9,9'-dicis-zeta-carotene + a quinone | catalyzed by zeta-carotene desaturases CrtQa and CrtQb | Nostoc sp. | 7,9,9'-tricis-neurosporene + a quinol | - |
? | |
9,9'-dicis-zeta-carotene + a quinone | catalyzed by zeta-carotene desaturases CrtQa and CrtQb | Nostoc sp. PCC 7120 | 7,9,9'-tricis-neurosporene + a quinol | - |
? | |
additional information | strain PCC 7120 contains two completely unrelated zeta-carotene desaturases CrtQa and CrtQb, which differ in their preferred utilization of zeta-carotene Z isomers. CrtQa converts zeta-carotene isomers that are poorly metabolized by CrtQb and CrtQa still possesses the Z to E isomerase function of the ancestral desaturase CrtI. CrtQb is an enzyme with one molecule of tightly bound FAD and acts as a dehydrogenase transferring hydrogen to oxidized plastoquinone. CrtQb yields only trace amounts of 7,9-Z neurosporene and 7,9,7',9'-Z lycopene | Nostoc sp. | ? | - |
? | |
additional information | zeta-carotene desaturase CrtQb converts (9Z)-zeta-carotene efficiently into (7Z,9Z)-neurosporene but stops at this stage without substantial lycopene formation. (all-E)-zeta-carotene cannot be converted by CrtQb. Similarly to (9Z)-zeta-carotene, the (all-E)-isomer is efficiently converted by CrtQa, substrate specificities, overview | Nostoc sp. | ? | - |
? | |
additional information | strain PCC 7120 contains two completely unrelated zeta-carotene desaturases CrtQa and CrtQb, which differ in their preferred utilization of zeta-carotene Z isomers. CrtQa converts zeta-carotene isomers that are poorly metabolized by CrtQb and CrtQa still possesses the Z to E isomerase function of the ancestral desaturase CrtI. CrtQb is an enzyme with one molecule of tightly bound FAD and acts as a dehydrogenase transferring hydrogen to oxidized plastoquinone. CrtQb yields only trace amounts of 7,9-Z neurosporene and 7,9,7',9'-Z lycopene | Nostoc sp. PCC 7120 | ? | - |
? | |
additional information | zeta-carotene desaturase CrtQb converts (9Z)-zeta-carotene efficiently into (7Z,9Z)-neurosporene but stops at this stage without substantial lycopene formation. (all-E)-zeta-carotene cannot be converted by CrtQb. Similarly to (9Z)-zeta-carotene, the (all-E)-isomer is efficiently converted by CrtQa, substrate specificities, overview | Nostoc sp. PCC 7120 | ? | - |
? |
Synonyms | Comment | Organism |
---|---|---|
CrtQa | - |
Nostoc sp. |
CrtQb | - |
Nostoc sp. |
zeta-carotene desaturase | - |
Nostoc sp. |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
FAD | tightly bound to zeta-carotene desaturase CrtQb | Nostoc sp. |