title: Active Sites of Reduced Epidermal Fluorescence1 (REF1) Isoforms Contain Amino Acid Substitutions That Are Different between Monocots and Dicots.
abstract: Plant aldehyde dehydrogenases (ALDHs) play important roles in cell wall biosynthesis, growth, development, and tolerance to biotic and abiotic stresses. The Reduced Epidermal Fluorescence1 is encoded by the subfamily 2C of ALDHs and was shown to oxidise coniferaldehyde and sinapaldehyde to ferulic acid and sinapic acid in the phenylpropanoid pathway, respectively. This knowledge has been gained from works in the dicotyledon model species Arabidopsis thaliana then used to functionally annotate ALDH2C isoforms in other species, based on the orthology principle. However, the extent to which the ALDH isoforms differ between monocotyledons and dicotyledons has rarely been accessed side-by-side. In this study, we used a phylogenetic approach to address this question. We have analysed the ALDH genes in Brachypodium distachyon, alongside those of other sequenced monocotyledon and dicotyledon species to examine traits supporting either a convergent or divergent evolution of the ALDH2C/REF1-type proteins. We found that B. distachyon, like other grasses, contains more ALDH2C/REF1 isoforms than A. thaliana and other dicotyledon species. Some amino acid residues in ALDH2C/REF1 isoforms were found as being conserved in dicotyledons but substituted by non-equivalent residues in monocotyledons. One example of those substitutions concerns a conserved phenylalanine and a conserved tyrosine in monocotyledons and dicotyledons, respectively. Protein structure modelling suggests that the presence of tyrosine would widen the substrate-binding pocket in the dicotyledons, and thereby influence substrate specificity. We discussed the importance of these findings as new hints to investigate why ferulic acid contents and cell wall digestibility differ between the dicotyledon and monocotyledon species.
authors: Department of Biology, Rutgers University, Camden, New Jersey, United States of America.
authors: Tagnon D
authors: TD
authors: Missihoun
authors: Department of Biology, Rutgers University, Camden, New Jersey, United States of America.|Center for Computational and Integrative Biology, Rutgers University, Camden, New Jersey, United States of America.
authors: Simeon O
authors: SO
authors: Kotchoni
authors: Institute of Molecular Physiology and Biotechnology of Plants (IMBIO), University of Bonn, Bonn, Germany.
authors: Dorothea
authors: D
authors: Bartels
authors: Peta
authors: P
authors: Bonham-Smith
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000737:chemistry* / Q000235:genetics*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001482:Base Composition; D001483:Base Sequence; D058431:Brachypodium / Q000235:genetics; D002384:Catalysis; D020134:Catalytic Domain / Q000235:genetics; D003062:Codon; D007527:Isoenzymes; D008958:Models, Molecular; D005810:Multigene Family; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics*; D011487:Protein Conformation
chemical_list: D003062:Codon; D007527:Isoenzymes; D010940:Plant Proteins; D000444:Aldehyde Dehydrogenase