来自里氏木霉的新型内切葡聚糖酶EGIII：基因与酶的特性研究

EGIII, a new endoglucanase from Trichoderma reesei: the characterization of both gene and enzyme.

作者信息

Saloheimo M, Lehtovaara P, Penttilä M, Teeri T T, Ståhlberg J, Johansson G, Pettersson G, Claeyssens M, Tomme P, Knowles J K

机构信息

Biotechnical Laboratory, VTT, Espoo, Finland.

出版信息

Gene. 1988;63(1):11-22. doi: 10.1016/0378-1119(88)90541-0.

DOI:10.1016/0378-1119(88)90541-0

PMID:3384334

Abstract

A novel endoglucanase from Trichoderma reesei, EGIII, has been purified and its catalytic properties have been studied. The gene for that enzyme (egl3) and cDNA have been cloned and sequenced. The deduced EGIII protein shows clear sequence homology to a Schizophyllum commune enzyme (M. Yaguchi, personal communication), but is very different from the three other T. reesei cellulases with known structure. Nevertheless, all the four T. reesei cellulases share two common, adjacent sequence domains, which apparently can be removed by proteolysis. These homologous sequences reside at the N termini of EGIII and the cellobiohydrolase CBHII, but at the C termini of EGI and CBHI. Comparison of the fungal cellulase structures has led to re-evaluation of hypotheses concerning the localization of the active sites.

摘要

一种来自里氏木霉的新型内切葡聚糖酶EGIII已被纯化，并对其催化特性进行了研究。该酶的基因（egl3）和cDNA已被克隆和测序。推导的EGIII蛋白与裂褶菌的一种酶显示出明显的序列同源性（M. Yaguchi，个人交流），但与其他三种已知结构的里氏木霉纤维素酶非常不同。然而，所有四种里氏木霉纤维素酶都共享两个相邻的共同序列结构域，显然可以通过蛋白水解去除。这些同源序列位于EGIII和纤维二糖水解酶CBHII的N端，但位于EGI和CBHI的C端。真菌纤维素酶结构的比较导致了对有关活性位点定位假设的重新评估。