Cloned (Comment) | Organism |
---|---|
gene D6, recombinant expression in Saccharomyces | Glossomastix chrysoplasta |
gene desI, recombinant expression in Saccharomyces | Thalassiosira pseudonana |
Protein Variants | Comment | Organism |
---|---|---|
D313I | site-directed mutagenesis, mutant shows slightly reduced activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
D367H | site-directed mutagenesis, mutant shows similar activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
F310L | site-directed mutagenesis, mutant shows similar activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
H360D | site-directed mutagenesis, mutant shows slightly reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
H381N | site-directed mutagenesis, mutant shows slightly reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
I306L | site-directed mutagenesis, mutant shows slightly reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
I390L | site-directed mutagenesis, mutant shows similar activity with linoleoyl-CoA and reduced activity with alpha-linolenoyl-CoA compared to the wild-type enzyme | Glossomastix chrysoplasta |
L303F | site-directed mutagenesis, mutant shows slightly reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
L383I | site-directed mutagenesis, mutant shows slightly reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
M384S/M385 | site-directed mutagenesis, mutant shows reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
M384S/M385L | site-directed mutagenesis, mutant shows significantly increased activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
additional information | construction of chimeric enzymes of delta6 desaturases from Glossomastix chrysoplasta and Thalassiosira pseudonana, chimera 7 with GcFADS2 residues 285-315 replaced by TpFADS2 residues 291-324 shows about 5fold increased activity with both substrates compared to the wild-type enzyme, the catalytic efficiency of chimera 9 with GcFADS2 residues 359-458 replaced by TpFADS2 residues 370-484 is also increased. The other chimeras exhibit a catalytic efficiency not significantly different both substrates compared with that exhibited by wild-type GcFADS2/TpFADS2. Fatty acid contents of wild-type and mutant strains, overview | Glossomastix chrysoplasta |
additional information | construction of chimeric enzymes of delta6 desaturases from Glossomastix chrysoplasta and Thalassiosira pseudonana, e.g. chimera 16 with TpFADS2 residues 291-324 replaced by GcFADS2 residues 285-315 shows decreased activity with both substrates compared to the wild-type enzyme. The replacement of the aa359-458 region of GcFADS2 results in a significant reduction in catalytic activity against both substrates, such that chimera 18 exhibits a decreased catalytic efficiency which represents the lowest rate observed among the TpFADS2 chimeras. The other chimeras exhibit a catalytic efficiency not significantly different both substrates compared with that exhibited by wild-type GcFADS2/TpFADS2. Fatty acid contents of wild-type an dmutant strains, overview | Thalassiosira pseudonana |
N388H | site-directed mutagenesis, mutant shows similar activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
S306T | site-directed mutagenesis, mutant shows similar activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
S322A | site-directed mutagenesis, mutant shows reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
S322A | site-directed mutagenesis, mutant shows highly increased activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
T299S | site-directed mutagenesis, mutant shows slightly reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
T302V | site-directed mutagenesis, the mutant shows reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
T302V | site-directed mutagenesis, mutant shows highly increased activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
T302V | site-directed mutagenesis, mutant shows potently increased activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
Y375F | site-directed mutagenesis, mutant shows reduced activity compared to the wild-type enzyme | Thalassiosira pseudonana |
Y375F | site-directed mutagenesis, mutant shows significantly increased activity compared to the wild-type enzyme | Glossomastix chrysoplasta |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | Michaelis-Menten kinetics | Glossomastix chrysoplasta | |
additional information | - |
additional information | Michaelis-Menten kinetics | Thalassiosira pseudonana |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
endoplasmic reticulum membrane | a transmembrane enzyme | Glossomastix chrysoplasta | 5789 | - |
endoplasmic reticulum membrane | a transmembrane enzyme | Thalassiosira pseudonana | 5789 | - |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
alpha-linolenoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | Glossomastix chrysoplasta | - |
stearidonoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? | |
alpha-linolenoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | Thalassiosira pseudonana | - |
stearidonoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? | |
linoleoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | Glossomastix chrysoplasta | - |
gamma-linolenoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? | |
linoleoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | Thalassiosira pseudonana | - |
gamma-linolenoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Glossomastix chrysoplasta | Q49S39 | - |
- |
Thalassiosira pseudonana | Q4G2T1 | - |
- |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
alpha-linolenoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ = stearidonoyl-CoA + 2 ferricytochrome b5 + 2 H2O | molecular mechanisms underlying catalytic activity of delta 6 desaturase | Thalassiosira pseudonana | |
linoleoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ = gamma-linolenoyl-CoA + 2 ferricytochrome b5 + 2 H2O | molecular mechanisms underlying catalytic activity of delta 6 desaturase | Glossomastix chrysoplasta | |
linoleoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ = gamma-linolenoyl-CoA + 2 ferricytochrome b5 + 2 H2O | molecular mechanisms underlying catalytic activity of delta 6 desaturase | Thalassiosira pseudonana |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
alpha-linolenoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | - |
Glossomastix chrysoplasta | stearidonoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? | |
alpha-linolenoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | - |
Thalassiosira pseudonana | stearidonoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? | |
alpha-linolenoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | preferred substrate | Glossomastix chrysoplasta | stearidonoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? | |
linoleoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | - |
Glossomastix chrysoplasta | gamma-linolenoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? | |
linoleoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | - |
Thalassiosira pseudonana | gamma-linolenoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? | |
linoleoyl-CoA + 2 ferrocytochrome b5 + O2 + 2 H+ | preferred substrate | Thalassiosira pseudonana | gamma-linolenoyl-CoA + 2 ferricytochrome b5 + 2 H2O | - |
? |
Synonyms | Comment | Organism |
---|---|---|
delta 6 desaturase | - |
Glossomastix chrysoplasta |
delta 6 desaturase | - |
Thalassiosira pseudonana |
DesI | - |
Thalassiosira pseudonana |
FADS2 | - |
Glossomastix chrysoplasta |
FADS2 | - |
Thalassiosira pseudonana |
GcFADS2 | - |
Glossomastix chrysoplasta |
TpFADS2 | - |
Thalassiosira pseudonana |
General Information | Comment | Organism |
---|---|---|
additional information | structure-function relationship, domain-swapping approach, two regions are essential to the catalytic mechanism: one that extends from the end of the fourth to the beginning of the fifth cytoplasmic transmembrane domain, and another that includes the C-terminal region that occurs after the sixth cytoplasmic transmembrane domain. Fatty acid contents of wild-type an dmutant strains, overview | Thalassiosira pseudonana |
additional information | structure-function relationship, domain-swapping approach, two regions are essential to the catalytic mechanism: one that extends from the end of the fourth to the beginning of the fifth cytoplasmic transmembrane domain, and another that includes the C-terminal region that occurs after the sixth cytoplasmic transmembrane domain. Fatty acid contents of wild-type and mutant strains, overview | Glossomastix chrysoplasta |
physiological function | delta 6 desaturase (FADS2) is a critical bifunctional enzyme required for polyunsaturated fatty acid biosynthesis, high catalytic activity of FADS2s from Glossomastix chrysoplasta. It controls the conversion of linoleoyl-CoA and alpha-linolenoyl-CoA to gamma-linolenic acid and stearidonic acid, respectively | Glossomastix chrysoplasta |
physiological function | delta 6 desaturase (FADS2) is a critical bifunctional enzyme required for polyunsaturated fatty acid biosynthesis, high catalytic activity of FADS2s from Thalassiosira pseudonana. It controls the conversion of linoleoyl-CoA and alpha-linolenoyl-CoA to gamma-linolenic acid and stearidonic acid, respectively | Thalassiosira pseudonana |