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MetaCyc Enzyme: very-long-chain 3-hydroxyacyl-CoA dehydratase

Gene: PAS2 Accession Numbers: AT5G10480 (MetaCyc), At5g10480

Synonyms: HACD, very-long-chain hydroxy fatty-acyl-CoA dehydratase

Species: Arabidopsis thaliana col

Component of: fatty acid elongase complex

Summary:
Very-long-chain fatty acids (VLCFAs) are synthesized as acyl-CoAs by the endoplasmic reticulum-localized elongase multiprotein complex. The PAS2 gene from Arabidopsis thaliana col is a homolog of the PHS1 gene from the yeast Saccharomyces cerevisiae and encodes one of the elongase proteins - very-long-chain 3-hydroxyacyl-CoA dehydratase.

Very-long-chain fatty acids are involved in developmental patterning in Arabidopsis [Roudier10]. Complete loss of PAS2 is embryo lethal. However, PAS2 mutants that have leaky alleles (that still produce a small amount of wild-type protein) accumulate 3-hydroxy-acyl-CoA intermediates and suffer from developmental defects [Bach08]. The mutants were characterized by a general reduction of VLCFA pools in seed storage triacylglycerols, cuticular waxes, and complex sphingolipids. Expression of yeast PHS1 in the mutant complemented the developmental defects and prevented the accumulation of long chain bases [Bach08].

Conversely, expression of the PAS2 protein in PHS1 yeast mutant eliminated the cytokinesis defects and sphingolipid long chain base overaccumulation that are typical to that mutant [Bach08].

PAS2 is associated in the endoplasmic reticulum with the enoyl-CoA reductase CER10, the fourth enzyme of the elongase complex.

Locations: endoplasmic reticulum membrane

Molecular Weight of Polypeptide: 25.327 kD (from nucleotide sequence)

Unification Links: ArrayExpress:Q8VZB2 , Entrez-gene:830912 , PhylomeDB:Q8VZB2 , Phytozome Plant Orthologs:AT5G10480.1 , Pride:Q8VZB2 , String:3702.AT5G10480.1-P , TAIR:AT5G10480 , UniProt:Q8VZB2

Relationship Links: InterPro:IN-FAMILY:IPR007482 , Panther:IN-FAMILY:PTHR11035 , Pfam:IN-FAMILY:PF04387

Gene-Reaction Schematic: ?

Instance reactions of [a very-long-chain (3R)-3-hydroxyacyl-CoA → a very-long-chain trans-2,3-dehydroacyl-CoA + H2O] (4.2.1.134):
i7: (3R)-3-hydroxy-behenoyl-CoA → trans-docos-2-enoyl-CoA + H2O (4.2.1.134)

i8: (3R)-3-hydroxy-cerotoyl-CoA → trans-cerot-2-enoyl-CoA + H2O (4.2.1.134)

Instance reaction of [a (3S)-3-hydroxyacyl-CoA ← a trans-2-enoyl-CoA + H2O] (4.2.1.17):
i6: (3R)-3-hydroxy-lignoceroyl-CoA → trans-lignocer-2-enoyl-CoA + H2O (4.2.1.134)

Instance reactions of [a very-long-chain (3R)-3-hydroxyacyl-CoA + NADP+ ← a very-long-chain oxoacyl-CoA + NADPH + H+] (1.1.1.330):
i3: (3R)-3-hydroxy-behenoyl-CoA + NADP+ ← 3-oxo-behenoyl-CoA + NADPH + H+ (1.1.1.330)

i4: (3R)-3-hydroxy-cerotoyl-CoA + NADP+ ← 3-oxo-cerotoyl-CoA + NADPH + H+ (1.1.1.330)

i5: (3R)-3-hydroxy-lignoceroyl-CoA + NADP+ ← 3-oxo-lignoceroyl-CoA + NADPH + H+ (1.1.1.330)

Instance reactions of [a very-long-chain 2,3,4-saturated fatty acyl CoA + NADP+ ← a very-long-chain trans-2,3-dehydroacyl-CoA + NADPH + H+] (1.3.1.93):
i1: lignoceroyl-CoA + NADP+trans-lignocer-2-enoyl-CoA + NADPH + H+ (1.3.1.93)

i2: cerotoyl-CoA + NADP+trans-cerot-2-enoyl-CoA + NADPH + H+ (1.3.1.93)

GO Terms:

Cellular Component: GO:0005789 - endoplasmic reticulum membrane [Bach08]

Credits:
Revised 06-Apr-2012 by Caspi R , SRI International


Enzymatic reaction of: 3-hydroxy-cerotoyl-CoA dehydratase (very-long-chain 3-hydroxyacyl-CoA dehydratase)

EC Number: 4.2.1.134

(3R)-3-hydroxy-cerotoyl-CoA <=> trans-cerot-2-enoyl-CoA + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: very long chain fatty acid biosynthesis II


Enzymatic reaction of: 3-hydroxy-lignoceroyl-CoA dehydratase (very-long-chain 3-hydroxyacyl-CoA dehydratase)

EC Number: 4.2.1.134

(3R)-3-hydroxy-lignoceroyl-CoA <=> trans-lignocer-2-enoyl-CoA + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: very long chain fatty acid biosynthesis II


Enzymatic reaction of: 3-hydroxy-behenoyl-CoA dehydratase (very-long-chain 3-hydroxyacyl-CoA dehydratase)

EC Number: 4.2.1.134

(3R)-3-hydroxy-behenoyl-CoA <=> trans-docos-2-enoyl-CoA + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: very long chain fatty acid biosynthesis II


Enzymatic reaction of: 3-hydroxy-arachidoyl-CoA dehydratase (very-long-chain 3-hydroxyacyl-CoA dehydratase)

EC Number: 4.2.1.134

(3R)-3-hydroxy-arachidoyl-CoA <=> trans-arachido-2-enoyl-CoA + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: very long chain fatty acid biosynthesis II


Enzymatic reaction of: very-long-chain 3-hydroxyacyl-CoA dehydratase

EC Number: 4.2.1.134

a very-long-chain (3R)-3-hydroxyacyl-CoA <=> a very-long-chain trans-2,3-dehydroacyl-CoA + H2O

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the direction shown.

In Pathways: very long chain fatty acid biosynthesis II , very long chain fatty acid biosynthesis I


Subunit of: fatty acid elongase complex

Species: Arabidopsis thaliana col

Subunit composition of fatty acid elongase complex = [CER6][CER10][PAS2][KCR1]
         very-long-chain 3-ketoacyl-CoA synthase = CER6 (extended summary available)
         very-long-chain enoyl-CoA reductase = CER10 (extended summary available)
         very-long-chain 3-hydroxyacyl-CoA dehydratase = PAS2 (extended summary available)
         very-long-chain 3-oxoacyl-CoA reductase = KCR1 (summary available)


References

Bach08: Bach L, Michaelson LV, Haslam R, Bellec Y, Gissot L, Marion J, Da Costa M, Boutin JP, Miquel M, Tellier F, Domergue F, Markham JE, Beaudoin F, Napier JA, Faure JD (2008). "The very-long-chain hydroxy fatty acyl-CoA dehydratase PASTICCINO2 is essential and limiting for plant development." Proc Natl Acad Sci U S A 105(38);14727-31. PMID: 18799749

Roudier10: Roudier F, Gissot L, Beaudoin F, Haslam R, Michaelson L, Marion J, Molino D, Lima A, Bach L, Morin H, Tellier F, Palauqui JC, Bellec Y, Renne C, Miquel M, Dacosta M, Vignard J, Rochat C, Markham JE, Moreau P, Napier J, Faure JD (2010). "Very-long-chain fatty acids are involved in polar auxin transport and developmental patterning in Arabidopsis." Plant Cell 22(2);364-75. PMID: 20145257


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Mon Dec 22, 2014, biocyc13.