6lpv
From Proteopedia
structure of Spermidine hydroxycinnamoyl transferases from Arabidopsis thaliana
Structural highlights
FunctionSHT_ARATH Hydroxycinnamoyl transferase involved in the conjugation of feruloyl CoA to spermidine (PubMed:19077165, PubMed:19762055, PubMed:33519864). Catalyzes the three conjugating steps required for the biosynthesis of N(1),N(4),N(8)-triferuloyl-spermidine (PubMed:19077165, PubMed:33519864). Spermidine is the only acceptor substrate while feruloyl CoA > caffeoyl CoA > coumaroyl CoA > cinnamoyl CoA >> sinapoyl CoA are efficient acyl donors. No activity with hydroxyferuloyl CoA (PubMed:19077165). Required for the biosynthesis of these conjugated spermidine derivatives, specifically in anther tapetum (PubMed:22912643).[1] [2] [3] [4] Publication Abstract from PubMedPhenolamides represent one of the largest classes of plant-specialized secondary metabolites and function in diverse physiological processes, including defense responses and development. The biosynthesis of phenolamides requires the BAHD-family acyltransferases, which transfer acyl-groups from different acyl-donors specifically to amines, the acyl-group acceptors. However, the mechanisms of substrate specificity and multisite-acylation of the BAHD-family acyltransferases remain poorly understood. In this study, we provide a structural and biochemical analysis of AtSHT and AtSDT, two representative BAHD-family members that catalyze the multisite acylation of spermidine but show different product profiles. By determining the structures of AtSHT and AtSDT and using structure-based mutagenesis, we identified the residues important for substrate recognition in AtSHT and AtSDT and hypothesized that the acyl acceptor spermidine might adopt a free-rotating conformation in AtSHT, which can undergo mono-, di-, or tri-acylation; while the spermidine molecule in AtSDT might adopt a linear conformation, which only allows mono- or di-acylation to take place. In addition, through sequence similarity network (SSN) and structural modeling analysis, we successfully predicted and verified the functions of two uncharacterized Arabidopsis BAHD acyltransferases, OAO95042.1 and NP_190301.2, which use putrescine as the main acyl-acceptor. Our work provides not only an excellent starting point for understanding multisite acylation in BAHD-family enzymes, but also a feasible methodology for predicting possible acyl acceptor specificity of uncharacterized BAHD-family acyltransferases. Structural and Biochemical Insights Into Two BAHD Acyltransferases (AtSHT and AtSDT) Involved in Phenolamide Biosynthesis.,Wang C, Li J, Ma M, Lin Z, Hu W, Lin W, Zhang P Front Plant Sci. 2021 Jan 13;11:610118. doi: 10.3389/fpls.2020.610118. , eCollection 2020. PMID:33519864[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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