4pxn

Publication Abstract from PubMed

Aldehyde dehydrogenases (ALDHs) are responsible for oxidation of biogenic aldehyde intermediates as well as for cell detoxification from aldehydes generated during lipid peroxidation. So far, 13 ALDH families have been described in plants. Here, we provide a detailed biochemical characterization of plant ALDH2 and ALDH7 families by analyzing maize and pea ALDH7 (ZmALDH7 and PsALDH7) and four maize cytosolic ALDH2 isoforms RF2C, RF2D, RF2E and RF2F (the first maize ALDH2 was discovered as a fertility restorer RF2A). We report the crystal structures of ZmALDH7, RF2C and RF2F at high resolution. The ZmALDH7 structure shows that the three conserved residues Glu120, Arg300 and Thr302 in the ALDH7 family are located in the substrate binding site and are specific for this family. Our kinetic analysis demonstrates that alpha-aminoadipic semialdehyde, a lysine catabolism intermediate, is the preferred substrate for plant ALDH7. In contrast, aromatic aldehydes including benzaldehyde, anisaldehyde, cinnamaldehyde, coniferaldehyde and sinapaldehyde are the best substrates for cytosolic ALDH2. In line with these results, the crystal structures of RF2C and RF2F reveal that their substrate binding sites are similar and formed by an aromatic cluster mainly composed of phenylalanine residues and several nonpolar residues. Gene expression studies indicate that RF2C gene, which is strongly expressed in all organs, appears essential suggesting that the crucial role of the enzyme would certainly be linked to the cell wall formation using aldehydes from phenylpropanoid pathway as substrates. Finally, plant ALDH7 may significantly contribute to osmoprotection, because it oxidizes several aminoaldehydes leading to products known as osmolytes.

Role and structural characterization of plant aldehyde dehydrogenases from family 2 and family 7.,Koncitikova R, Vigouroux A, Kopecna M, Andree T, Bartos J, Sebela M, Morera S, Kopecny D Biochem J. 2015 Mar 3. PMID:25734422^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.