4ud8
AtBBE15AtBBE15
Structural highlights
FunctionBBE15_ARATH Required for endosperm development and polar nuclei fusion (PubMed:15634699). Mediates oxidation of p-hydroxylated derivatives of cinnamyl alcohol (i.e. the monolignols p-coumaryl-, coniferyl-, and sinapyl alcohol) to their corresponding aldehydes. Can also use the beta-O-glycosylated form of coniferyl alcohol (coniferin) as substrate, but is much less efficient towards cinnamyl alcohol. The electron acceptor required for these reactions is not known, but does not seem to be dioxygen (PubMed:26037923).[1] [2] Publication Abstract from PubMedPlant genomes contain a large number of genes encoding for berberine bridge enzyme (BBE)-like enzymes. Despite the widespread occurrence and abundance of this protein family in the plant kingdom, the biochemical function remains largely unexplored. In this study, we have expressed two members of the BBE-like enzyme family from Arabidopsis thaliana in the host organism Komagataella pastoris. The two proteins, termed AtBBE-like 13 and AtBBE-like 15, were purified, and their catalytic properties were determined. In addition, AtBBE-like 15 was crystallized and structurally characterized by x-ray crystallography. Here, we show that the enzymes catalyze the oxidation of aromatic allylic alcohols, such as coumaryl, sinapyl, and coniferyl alcohol, to the corresponding aldehydes and that AtBBE-like 15 adopts the same fold as vanillyl alcohol oxidase as reported previously for berberine bridge enzyme and other FAD-dependent oxidoreductases. Further analysis of the substrate range identified coniferin, the glycosylated storage form of coniferyl alcohol, as a substrate of the enzymes, whereas other glycosylated monolignols were rather poor substrates. A detailed analysis of the motifs present in the active sites of the BBE-like enzymes in A. thaliana suggested that 14 out of 28 members of the family might catalyze similar reactions. Based on these findings, we propose a novel role of BBE-like enzymes in monolignol metabolism that was previously not recognized for this enzyme family. Oxidation of Monolignols by Members of the Berberine Bridge Enzyme Family Suggests a Role in Plant Cell Wall Metabolism.,Daniel B, Pavkov-Keller T, Steiner B, Dordic A, Gutmann A, Nidetzky B, Sensen CW, van der Graaff E, Wallner S, Gruber K, Macheroux P J Biol Chem. 2015 Jul 24;290(30):18770-81. doi: 10.1074/jbc.M115.659631. Epub, 2015 Jun 2. PMID:26037923[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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