Teeri T T, Lehtovaara P, Kauppinen S, Salovuori I, Knowles J
Gene. 1987;51(1):43-52. doi: 10.1016/0378-1119(87)90472-0.
Fungal cellobiohydrolases are unique enzymes capable of degrading highly ordered crystalline cellulose. We present here the isolation and complete sequence analysis of the chromosomal and cDNA copies of the structural gene (cbh2) coding for one of the major cellobiohydrolases (CBH II) of Trichoderma reesei. We also present data on expression of the cbh2 gene and show that the transcription start points of the cbh2 gene are heterogeneous and are located 32 to 52 bp downstream from a putative TATA box. The derived CBH II protein sequence is 471 amino acids long and the coding region is interrupted by three short introns. Most of the CBH II protein bears no apparent resemblance to CBH I and endoglucanase I. However, a short region of extensive homology is found in all Trichoderma cellulases characterized so far, suggesting that this region is important for cellulose hydrolysis. The implications of this information with regard to the evolution of fungal cellulase genes and the enzymology of cellulose hydrolysis are discussed.
真菌纤维二糖水解酶是一类能够降解高度有序的结晶纤维素的独特酶类。我们在此展示了里氏木霉主要纤维二糖水解酶之一（CBH II）的结构基因（cbh2）的染色体拷贝和cDNA拷贝的分离及完整序列分析。我们还展示了关于cbh2基因表达的数据，并表明cbh2基因的转录起始点是异质的，位于假定的TATA框下游32至52个碱基对处。推导的CBH II蛋白序列长471个氨基酸，编码区被三个短内含子打断。CBH II蛋白的大部分与CBH I和内切葡聚糖酶I没有明显相似性。然而，在迄今已鉴定的所有里氏木霉纤维素酶中都发现了一个短的广泛同源区域，这表明该区域对纤维素水解很重要。本文讨论了这些信息对真菌纤维素酶基因进化和纤维素水解酶学的意义。
