Department of Biological Sciences, California State University, East Bay, Hayward, CA 94542, USA.
Department of Physics, California State University, East Bay, Hayward, CA 94542, USA.
Int J Mol Sci. 2023 May 5;24(9):8297. doi: 10.3390/ijms24098297.
Participating in both biotic and abiotic stress responses, plant-specific class III peroxidases (PERs) show promise as candidates for crop improvement. The multigenic PER family is known to take part in diverse functions, such as lignin formation and defense against pathogens. Traditionally linked to hydrogen peroxide (HO) consumption, PERs can also produce reactive oxygen species (ROS), essential in tissue development, pathogen defense and stress signaling. The amino acid sequences of both orthologues and paralogues of PERs are highly conserved, but discovering correlations between sequence differences and their functional diversity has proven difficult. By combining meta-analysis of transcriptomic data and sequence alignments, we discovered a correlation between three key amino acid positions and gene expression in response to biotic and abiotic stresses. Phylogenetic analysis revealed evolutionary pressure on these amino acids toward stress responsiveness. Using AlphaFold modeling, we found unique interdomain and protein-heme interactions involving those key amino acids in stress-induced PERs. Plausibly, these structural interactions may act as "gate keepers" by preventing larger substrates from accessing the heme and thereby shifting PER function from consumption to the production of ROS.
参与生物和非生物胁迫反应，植物特异性 III 类过氧化物酶（PERs）有望成为作物改良的候选者。多基因 PER 家族已知参与多种功能，如木质素形成和抵御病原体。传统上与过氧化氢（HO）消耗有关，PERs 也可以产生活性氧（ROS），在组织发育、病原体防御和应激信号中必不可少。PERs 的同源物和同系物的氨基酸序列高度保守，但发现序列差异与其功能多样性之间的相关性一直很困难。通过结合转录组数据分析和序列比对的荟萃分析，我们发现了三个关键氨基酸位置与生物和非生物胁迫响应中基因表达之间的相关性。系统发育分析揭示了这些氨基酸在应激响应方面的进化压力。使用 AlphaFold 建模，我们发现了涉及应激诱导 PERs 中这些关键氨基酸的独特的结构域间和蛋白质血红素相互作用。合理地，这些结构相互作用可能充当“守门员”，防止较大的底物进入血红素，从而将 PER 功能从消耗转变为 ROS 的产生。
