PpASCL, a moss ortholog of anther‐specific chalcone synthase‐like enzymes, is a hydroxyalkylpyrone synthase involved in an evolutionarily conserved sporopollenin biosynthesis pathway
| Autor: | Ralf Reski, Dae-Yeon Suh, Christina Jepson, Sun Young Kim, Andrew G. H. Wee, Che C. Colpitts, Carl J. Douglas, Sarah E. Posehn, Sung-Soo Kim, Gertrud Wiedemann |
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| Rok vydání: | 2011 |
| Předmět: |
Models
Molecular Spores Chalcone synthase Physiology Molecular Sequence Data Arabidopsis Flowers Plant Science Biology Genes Plant Physcomitrella patens Substrate Specificity Evolution Molecular Biopolymers Sporopollenin Gene Expression Regulation Plant Catalytic Domain Polyketide synthase Amino Acid Sequence Gene Conserved Sequence Oligonucleotide Array Sequence Analysis Expressed sequence tag Sequence Homology Amino Acid ATP synthase biology.organism_classification Carotenoids Bryopsida Biosynthetic Pathways Intramolecular Oxidoreductases Kinetics Biochemistry Organ Specificity Pyrones Biocatalysis biology.protein Chromatography Thin Layer Polyketide Synthases Sequence Alignment Acyltransferases |
| Zdroj: | New Phytologist. 192:855-868 |
| ISSN: | 1469-8137 0028-646X |
| Popis: | Summary • Sporopollenin is the main constituent of the exine layer of spore and pollen walls. Recently, several Arabidopsis genes, including polyketide synthase A (PKSA), which encodes an anther-specific chalcone synthase-like enzyme (ASCL), have been shown to be involved in sporopollenin biosynthesis. The genome of the moss Physcomitrella patens contains putative orthologs of the Arabidopsis sporopollenin biosynthesis genes. • We analyzed available P. patens expressed sequence tag (EST) data for putative moss orthologs of the Arabidopsis genes of sporopollenin biosynthesis and studied the enzymatic properties and reaction mechanism of recombinant PpASCL, the P. patens ortholog of Arabidopsis PKSA. We also generated structure models of PpASCL and Arabidopsis PKSA to study their substrate specificity. • Physcomitrella patens orthologs of Arabidopsis genes for sporopollenin biosynthesis were found to be expressed in the sporophyte generation. Similarly to Arabidopsis PKSA, PpASCL condenses hydroxy fatty acyl-CoA esters with malonyl-CoA and produces hydroxyalkyl a-pyrones that probably serve as building blocks of sporopollenin. The ASCL-specific set of Gly-Gly-Ala residues predicted by the models to be located at the floor of the putative active site is proposed to serve as the opening of an acyl-binding tunnel in ASCL. • These results suggest that ASCL functions together with other sporophytespecific enzymes to provide polyhydroxylated precursors of sporopollenin in a pathway common to land plants. |
| Databáze: | OpenAIRE |
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