Department of Biotechnology and Microbiology, Kannur University, Thalassery Campus, Palayad P.O., Kannur, 670661, Kerala, India.
Department of Biotechnology and Microbiology, Kannur University, Thalassery Campus, Palayad P.O., Kannur, 670661, Kerala, India.
Plant Physiol Biochem. 2020 Oct;155:683-696. doi: 10.1016/j.plaphy.2020.08.008. Epub 2020 Aug 15.
The accumulation of a metabolic by product - methylglyoxal above a minimal range can be highly toxic in all organisms. Stress induced elevation in methylglyoxal inactivates proteins and nucleic acids. Glutathione dependent glyoxalase enzymes like glyoxalase I and glyoxalase II together with glutathione independent glyoxalase III play inevitable role in methylglyoxal detoxification. Glyoxalase genes are generally conserved but with obvious exceptions. Mangroves being potent harsh land inhabitants, their internal organelles are constantly been exposed to elevated levels of methylglyoxal. First and foremost it is important to detect the presence of glyoxalases in mangroves. De novo transcriptome analysis of mangrove species Rhizophora mucronata Lam., identified eleven putative glyoxalase proteins (RmGLYI-1 to 5, RmGLYII-1 to 5 and RmGLYIII). Molecular characterization proposed PLN02300 or PLN02367 as the key domains of RmGLYI proteins. They possess molecular weight ranging from 26.45 to 32.53 kDa and may localize in cytosol or chloroplast. RmGLYII proteins of molecular weight 28.64-36 kDa, carrying PLN02398 or PLN02469 domains are expected to be localized in diverse cellular compartments. Cytosolic RmGLYIII with DJ-1/PfpI domain carries a molecular weight 26.4 kDa. Detailed structural analysis revealed monomeric nature of RmGLYI-1 and RmGLYII-1 whereas RmGLYIII is found to be homodimer. Molecular phylogenetic analysis and multiple sequence alignment specified conserved metal ion/substrate binding residues of RmGLY proteins. Estimation of relative expression of glyoxalases under salt stress indicated the prominence of RmGLYI and RmGLYII over RmGLYIII. The aforementioned prominence is supported by salt induced expression difference of glutathione metabolic enzymes and glutathione regulated transporter protein.
代谢副产物甲基乙二醛（Methylglyoxal）在最小范围内的积累对所有生物体都具有高度毒性。应激诱导的甲基乙二醛升高会使蛋白质和核酸失活。谷胱甘肽依赖的醛糖酶，如醛糖酶 I 和醛糖酶 II，以及谷胱甘肽独立的醛糖酶 III，在甲基乙二醛解毒中发挥着不可避免的作用。醛糖酶基因通常是保守的，但也有明显的例外。红树林是一种强有力的恶劣陆地生物，其内部细胞器经常暴露在高水平的甲基乙二醛中。首先，检测红树林中醛糖酶的存在非常重要。红树林物种红树（Rhizophora mucronata Lam.）的从头转录组分析，鉴定出 11 种推定的醛糖酶蛋白（RmGLYI-1 至 5、RmGLYII-1 至 5 和 RmGLYIII）。分子特征表明 PLN02300 或 PLN02367 是 RmGLYI 蛋白的关键结构域。它们的分子量范围为 26.45 至 32.53 kDa，可能定位于细胞质或叶绿体中。分子量为 28.64-36 kDa 的 RmGLYII 蛋白，携带 PLN02398 或 PLN02469 结构域，预计将定位于不同的细胞区室中。具有 DJ-1/PfpI 结构域的细胞质 RmGLYIII 携带 26.4 kDa 的分子量。详细的结构分析表明 RmGLYI-1 和 RmGLYII-1 为单体，而 RmGLYIII 为同源二聚体。分子系统发育分析和多重序列比对指定了 RmGLY 蛋白保守的金属离子/底物结合残基。盐胁迫下醛糖酶相对表达的估计表明，RmGLYI 和 RmGLYII 比 RmGLYIII 更为突出。谷胱甘肽代谢酶和谷胱甘肽调节转运蛋白的盐诱导表达差异支持了上述突出性。
