Characterization of a chromosomal segment showing xylanolytic activity from the symbiotic Sphingobacterium sp. TN19
2010
Zhou, Junpei | Meng, Kun | Yang, Peilong | Shi, Pengjun | Wang, Yaru | Luo, Huiying | Yao, Bin
A 37.5-kb chromosomal segment with 41.5% G+C content was cloned using genome walking method from Sphingobacterium sp. TN19, a symbiotic strain isolated from the gut of Batocera horsfieldi (Coleoptera, Cerambycidae) larvae. Twenty-three complete and two partial open reading frames (ORFs) were found in this region, and shared highest identities of 31.6-80.0% (11 of them <60%) to known sequences from the sources shared the common feature—fluid with low dissolved oxygen levels. These ORFs were organized uniquely in chromosome compared to that from other bacteria, and putatively involved in xylan and xylose metabolism. To confirm their putative functions, one xylanase gene (xynB19) and one arabinosidase gene (gh43A19), were hetero-expressed in Escherichia coli BL21 (DE3), respectively, and both the recombinant enzymes showed significant enzymatic activities. This result indicates that xylan degradation is a complex process involving various enzymes, and genome walking is an efficient method to obtain multiple genes.
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