Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília-DF, Brazil.
J Appl Microbiol. 2010 Apr;108(4):1187-98. doi: 10.1111/j.1365-2672.2009.04528.x. Epub 2009 Aug 19.
Penicillium echinulatum is effective for bioconversion processes. However, nothing is known about the molecular biology of its cellulolytic system. We describe for the first time the isolation, cloning and expression of a P. echinulatum cellulase cDNA (Pe-egl1) encoding a putative endoglucanase.
Pe-egl1 cDNA was identified from random sequencing of a P. echinulatum cDNA library. The deduced EGL1 protein possibly belongs to the glycosyl hydrolase family 5A, with 387 amino acid residues and strong similarity with other fungal endoglucanases. The cDNA was heterologously expressed in Pichia pastoris. The recombinant EGL1 secreted by a Pic. pastoris recombinant strain revealed the characteristics of particular interest: an optimal activity over a broad pH range (5.0-9.0), and an optimal temperature of 60 degrees C. The recombinant EGL1 also showed high thermostability (84% of residual activity after 1 h of pre-incubation at 70 degrees C). Calcium exerted a strong stimulatory effect over EGL1 activity.
Altogether, these results point to the potential application of this P. echinulatum endoglucanase in cellulose processing industries, particularly the textile one because of its biochemical properties.
The characterization and heterologous expression of the first P. echinulatun cDNA inaugurates the exploitation of this potential industrial micro-organism.
青霉属（Penicillium）中的棘孢青霉（Penicillium echinulatum）在生物转化过程中效果显著。然而，其纤维素分解系统的分子生物学方面仍不为人知。我们首次描述了棘孢青霉纤维素酶 cDNA（Pe-egl1）的分离、克隆和表达，该 cDNA 编码一种假定的内切葡聚糖酶。
从棘孢青霉菌 cDNA 文库的随机测序中鉴定出 Pe-egl1 cDNA。推测的 EGL1 蛋白可能属于糖苷水解酶家族 5A，由 387 个氨基酸残基组成，与其他真菌内切葡聚糖酶具有很强的相似性。该 cDNA 在巴斯德毕赤酵母（Pichia pastoris）中异源表达。毕赤酵母重组菌株分泌的重组 EGL1 具有以下特别引人关注的特性：在较宽的 pH 范围（5.0-9.0）内具有最佳活性，最佳温度为 60°C。重组 EGL1 还表现出较高的热稳定性（在 70°C 下预孵育 1 小时后仍保持 84%的残余活性）。钙离子对 EGL1 活性有很强的刺激作用。
综上所述，这些结果表明，这种棘孢青霉内切葡聚糖酶具有在纤维素加工工业，特别是纺织工业中应用的潜力，这归因于其生化特性。
棘孢青霉 cDNA 的特性描述和异源表达开创了这种潜在工业微生物的开发利用。
