| 摘要: |
| 纤维二糖水解酶I(CBH I)是生物降解纤维素的一种重要的外切酶,它作用于纤维素分子末端,水解β-1,4-糖苷键。纤维二糖水解酶由3个部分组成:具有催化活性的催化结构域,作用为锚定纤维素的纤维素结合域以及连接这两个结构域的一段短肽。已知催化结构域属于糖基水解酶家族7(GH7),纤维素结合域属于糖类结合模块家族1(CBM1)。为进一步探索CBHI编码基因之间的进化关系,本研究依据CBHI的结构域在GenBank数据库中搜索并鉴定CBHI编码基因并据此构建系统发育树。序列的平均长度为1 776 bp,平均GC含量为57.64％,平均转换颠换比为0.71,平均遗传距离为0.424。得出结论CBHI编码基因只存在于真菌中,是一个相对活跃的基因,它的进化与物种的进化有着密切的关系。 |
| 关键词: 纤维二糖水解酶I(CBHI) 系统进化 序列比对 |
| DOI：10.3969/j.issn.1672-5565.2013-04.20130411 |
| 分类号: |
| 基金项目: |
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| Phylogeny tree analysis of cellobiohydrolase I |
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CHEN Xiao-xiao, TIAN Xing-jun
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(School of life Science ,NanJing University, NanJing 210093,China)
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| Abstract: |
| Cellobiohydrolase I (CBHI) is an important exo-acting enzyme, playing a role in the conversion of cellulose to glucose by cutting the disaccharide cellobiose from the non-reducing end of the cellulose polymer chain. CBHI is composed of three parts: catalytic domain(CD), cellulose-binding domain(CBD) and a glycosylated linker peptide connecting CD and CBD. The CD of CBHI belongs to glycoside hydrolase family 7(GH7) while the CBD belongs to carbohydrate-binding module family 1 (CBM1). For the discovery of phylogenetic relationship between CBHI genes, this article searched and identified CBHI genes from GenBank according to the domain of CBHI and then did phylogeny tree analysis. The average length of the sequences is 1776bp and G+C content of them is 57.64％. The average transition／transversion rate ratio is 0.71. The average genetic distance is 0.424.The result stated that CBHI genes exist only in fungus. CBHI genes are relatively active and the evolution of CBHI genes is significantly related to the evolution of species. |
| Key words: Cellobiohydrolase I (CBHI) Phyletic Evolution Sequence Alignment |
