The multifunctional protein in peroxisomal beta-oxidation: structure and substrate specificity of the Arabidopsis thaliana protein MFP2

TY - JOUR

T1 - The multifunctional protein in peroxisomal beta-oxidation

T2 - structure and substrate specificity of the Arabidopsis thaliana protein MFP2

AU - Arent, Susan

AU - Christensen, Caspar Elo

AU - Pye, Valerie E

AU - Nørgaard, Allan

AU - Henriksen, Anette

PY - 2010/7/30

Y1 - 2010/7/30

N2 - Plant fatty acids can be completely degraded within the peroxisomes. Fatty acid degradation plays a role in several plant processes including plant hormone synthesis and seed germination. Two multifunctional peroxisomal isozymes, MFP2 and AIM1, both with 2-trans-enoyl-CoA hydratase and L-3-hydroxyacyl-CoA dehydrogenase activities, function in mouse ear cress (Arabidopsis thaliana) peroxisomal β-oxidation, where fatty acids are degraded by the sequential removal of two carbon units. A deficiency in either of the two isozymes gives rise to a different phenotype; the biochemical and molecular background for these differences is not known. Structure determination of Arabidopsis MFP2 revealed that plant peroxisomal MFPs can be grouped into two families, as defined by a specific pattern of amino acid residues in the flexible loop of the acylbinding pocket of the 2-trans-enoyl-CoA hydratase domain. This could explain the differences in substrate preferences and specific biological functions of the two isozymes. The in vitro substrate preference profiles illustrate that the Arabidopsis AIM1 hydratase has a preference for short chain acyl-CoAs compared with the Arabidopsis MFP2 hydratase. Remarkably, neither of the two was able to catabolize enoyl-CoA substrates longer than 14 carbon atoms efficiently, suggesting the existence of an uncharacterized long chain enoyl-CoA hydratase in Arabidopsis peroxisomes.

AB - Plant fatty acids can be completely degraded within the peroxisomes. Fatty acid degradation plays a role in several plant processes including plant hormone synthesis and seed germination. Two multifunctional peroxisomal isozymes, MFP2 and AIM1, both with 2-trans-enoyl-CoA hydratase and L-3-hydroxyacyl-CoA dehydrogenase activities, function in mouse ear cress (Arabidopsis thaliana) peroxisomal β-oxidation, where fatty acids are degraded by the sequential removal of two carbon units. A deficiency in either of the two isozymes gives rise to a different phenotype; the biochemical and molecular background for these differences is not known. Structure determination of Arabidopsis MFP2 revealed that plant peroxisomal MFPs can be grouped into two families, as defined by a specific pattern of amino acid residues in the flexible loop of the acylbinding pocket of the 2-trans-enoyl-CoA hydratase domain. This could explain the differences in substrate preferences and specific biological functions of the two isozymes. The in vitro substrate preference profiles illustrate that the Arabidopsis AIM1 hydratase has a preference for short chain acyl-CoAs compared with the Arabidopsis MFP2 hydratase. Remarkably, neither of the two was able to catabolize enoyl-CoA substrates longer than 14 carbon atoms efficiently, suggesting the existence of an uncharacterized long chain enoyl-CoA hydratase in Arabidopsis peroxisomes.

KW - Arabidopsis

KW - Arabidopsis Proteins

KW - Crystallography, X-Ray

KW - Fatty Acids

KW - Gene Expression Regulation, Plant

KW - Models, Biological

KW - Oxidation-Reduction

KW - Oxygen

KW - Peroxisomes

KW - Phenotype

KW - Protein Binding

KW - Protein Conformation

KW - Protein Isoforms

KW - Protein Structure, Tertiary

KW - Substrate Specificity

U2 - 10.1074/jbc.M110.106005

DO - 10.1074/jbc.M110.106005

M3 - Journal article

C2 - 20463021

SN - 0021-9258

VL - 285

SP - 24066

EP - 24077

JO - The Journal of Biological Chemistry

JF - The Journal of Biological Chemistry

IS - 31

ER -