Molecular identification and characterization of an acidic peptide:N-glycanase from tomato (Lycopersicum esculentum) fruits*
Molecular identification and characterization of an acidic peptide:N-glycanase from tomato (Lycopersicum esculentum) fruits*
复制标题
DOI：
10.1093/jb/mvp157
复制
发表时间：
2010-02-01
影响因子：
2.7
通讯作者：
Kimura, Yoshinobu
中科院分区：
文献类型：
--
作者：
Hossain, Md. Anowar;Nakano, Ryohei;Kimura, Yoshinobu
植物酸性肽：n -糖基化酶（PNGase）是一种去糖基化酶，被认为参与植物细胞中糖蛋白的分解代谢。然而，在植物分化或生长中所涉及的有形生理意义尚不清楚。在这项研究中，作为阐明游离n -聚糖和去n -糖基化机制在植物细胞发育中的生理作用的第一步，我们成功地在毕赤酵母中表达了番茄果实的cDNA，并在培养上清中鉴定了一种酸性肽：n -糖基化酶。pngase基因编码的蛋白是一个由588个氨基酸组成的单肽链，预测分子质量为65.8 kDa。重组番茄PNGase在pH 4.5和40℃条件下具有最佳的酶活性，不需要任何金属离子就能获得充分的酶活性，并能从糖肽中释放出n -聚糖。我们的系统发育分析表明，植物酸性PNGase与普遍存在的细胞质PNGase完全不同，并且参与与植物生长发育相关的不同的去n -糖基化机制。
Plant acidic peptide:N-glycanase (PNGase) is one of the deglycosylation enzymes and has been considered to be involved in the catabolism of glycoproteins in plant cells. However, the tangible physiological significance involved in plant differentiation or growth is yet unclear. In this study, as a first step to elucidate the physiological role of free N-glycans and the de-N-glycosylation machinery working in developing plant cells, we have succeeded in expressing a cDNA from tomato fruits in Pichia pastoris and identified an acidic peptide:N-glycanase in the culture supernatant. The PNGase-gene-encoded protein is a single polypeptide chain of 588 amino acids with a predicted molecular mass of 65.8 kDa. The deduced amino acid sequence showed 57.9% similarity with almond PNGase A. The recombinant tomato PNGase showed optimum activity at pH 4.5 and 40 degrees C. It did not require any metal ions for full enzymatic activity and could release the complex-type N-glycan from glycopeptides. Our phylogenetic analysis reveals that the plant acidic PNGase is completely different from the ubiquitous cytosolic PNGase and is involved in a different de-N-glycosylation mechanism associated with plant growth and development.