Source:
Generated By: https://synbiohub.org/public/igem/igem2sbol/1
Created by: David Puyraimond
Date created: 2007-07-09 11:00:00
Date modified: 2015-08-31 04:07:52
Diacylglycerol-Acyl-transferase (DGAT) for triglyceride synthesis
| Types | DnaRegion |
| Roles | Coding CDS |
| Sequences | BBa_I718002_sequence (Version 1) |
Description
- Which species is the enzyme from?
Acinetobacter calcoaceticus ADP1 (Gram negative bacterium)
- What reaction does it catalyze?
diacylglycerol + acyl-coA -> triglyceride + coA-SH
Studies employing total membrane fractions or extracts of recombinants E. coli strains revealed that this enzyme has a very broad substrate range, accepting long chain fatty alcohols and acyl-CoA esters ranging from C12 to C20 as well as monoacylglycerol as substrates (Kalscheuer, 2004)
- Does it work in E. coli?
Yes. The authors of the paper have shown that it works already in vitro after purification.
- Does it require anything?
Yes. DAG is already a compound of the phospholipid metabolism. E. coli has a Long Chain Fatty Acid (LCFA) transporter, FadL. Adding oleate in the LB medium (5mM) is probably needed.
- The four reactions where DAG is involved:
- ATP + a 1,2-diacylglycerol = ADP + an L-phosphatidate
- a 1,2-diacylglycerol + CDP-choline -> a - phosphatidylcholine + CMP
- an L-1-phosphatidyl-ethanolamine + KDO2-lipid IVA = a 1,2-diacylglycerol + phosphatidylethanolamine-KDO2-lipidA
- an MDO-O-glucose + an L-1-phosphatidyl-glycerol = a 1,2-diacylglycerol + an MDO-6-(glycerophospho)-D-glucose
- Another reactions catalyzed by DGAT?
Yes. DGAT is also an acyl-CoA fatty alcohol acyltransferase (wax ester synthase, WS) catalyzing the final condensation of acyl-CoA and fatty alcohol. Knowing that E.coli does not produce fatty alcohol, this reaction is probably not avaible in this bacteria.
- In vitro characterization of WS/DGAT:
The molecular weight is about 53 kDa, the enzyme probably acts as homodimer (Stoevken, 2005).
The highest activity was obtained at 40 - 45 ??C (Stoevken, 2005)
The WS reaction follows a Michaelis - Menten kinetic but the DGAT reaction fit neither Michaelis - Menten neither cooperative enzyme kinetics (Stoevken, 2005).
Palmitoyl-CoA is accepted with highest specificity (Stoevken, 2005).
In Acinetobacter ADP1, the enzyme is associated with lipids inclusions but also with the membrane and a minor amount in the cytoplasm (Stoevken, 2005). In recombinant E.coli, the majority of WS/DGAT was membrane-associated but to some extent also located in the cytosolic fraction (Stoevken, 2005).
Notes
We mutagenized Pst-1 site in position 1062 after ATG.We mutagenized stop codon TAAAAA into TAATAA to conform with BioBrick standards.
We added in 5' a strong RBS (BBa_B0030) and prefixe biobrick (BBa_G00000).
In 3', we added suffixe biobrick (BBa_G00001).
Source
- Acinetobacter calcoaceticus ADP1
- Accession number: AF529086
- Kalscheuer,R. and Steinbuchel,A. A Novel Bifunctional Wax Ester Synthase/Acyl-CoA:Diacylglycerol Acyltransferase Mediates Wax Ester and Triacylglycerol Biosynthesis in Acinetobacter calcoaceticus ADP1. J. Biol. Chem. 278 (10), 8075-8082 (2003)