Covert S F, Vanden Wymelenberg A, Cullen D
Department of Bacteriology, University of Wisconsin-Madison 53706.
Appl Environ Microbiol. 1992 Jul;58(7):2168-75. doi: 10.1128/aem.58.7.2168-2175.1992.
Restriction mapping and sequence analysis of cosmid clones revealed a cluster of three cellobiohydrolase genes in Phanerochaete chrysosporium. P. chrysosporium cbh1-1 and cbh1-2 are separated by only 750 bp and are located approximately 14 kb upstream from a cellulase gene previously cloned from P. chrysosporium (P. Sims, C. James, and P. Broda, Gene 74:411-422, 1988). Within a well-conserved region, the deduced amino acid sequences of P. chrysosporium cbh1-1 and cbh1-2 are, respectively, 80 and 69% homologous to that of the Trichoderma reesei cellobiohydrolase I gene. The conserved cellulose-binding domain typical of microbial cellulases is absent from cbh1-1. Transcript levels of the three P. chrysosporium genes varied substantially, depending on culture conditions. cbh1-1 and cbh1-2 were not induced in the presence of cellulose, nor did they appear to be subject to glucose repression. Therefore, aspects of the chromosomal organization, structure, and transcription of these genes are unlike those of any previously described cellulase genes.
黏粒克隆的限制酶切图谱分析和序列分析显示，在黄孢原毛平革菌中存在一组三个纤维二糖水解酶基因。黄孢原毛平革菌的cbh1-1和cbh1-2仅相隔750 bp，位于先前从黄孢原毛平革菌克隆的一个纤维素酶基因上游约14 kb处（P. Sims、C. James和P. Broda，《基因》74:411 - 422，1988）。在一个保守区域内，黄孢原毛平革菌cbh1-1和cbh1-2推导的氨基酸序列与里氏木霉纤维二糖水解酶I基因的序列分别具有80%和69%的同源性。cbh1-1中没有微生物纤维素酶典型的保守纤维素结合结构域。这三个黄孢原毛平革菌基因的转录水平根据培养条件有很大差异。cbh1-1和cbh1-2在纤维素存在时不被诱导，似乎也不受葡萄糖阻遏。因此，这些基因的染色体组织、结构和转录方面与任何先前描述的纤维素酶基因都不同。
