Complete genome of the cellulolytic thermophile Acidothermus cellulolyticus 11B provides insights into its ecophysiological and evolutionary adaptations
Complete genome of the cellulolytic thermophile Acidothermus cellulolyticus 11B provides insights into its ecophysiological and evolutionary adaptations
复制标题
DOI：
10.1101/gr.084848.108
复制
发表时间：
2009-06-01
期刊：
影响因子：
7
通讯作者：
Berry, Alison M.
中科院分区：
文献类型：
--
作者：
Barabote, Ravi D.;Xie, Gary;Berry, Alison M.
在这里，我们提出了完整的2.4-Mb的基因组的纤维素分解放线菌嗜热酸嗜热菌11B。在基因组中鉴定了新的分泌型糖苷水解酶和碳水化合物酯酶，揭示了远大于先前表征的多种生物质降解酶谱，并提高了该生物体的工业价值。这些水解酶的相当大的一部分分解植物细胞壁，其余的要么降解真菌细胞壁中的组分，要么代谢储存碳水化合物，如糖原和海藻糖，暗示这些不同的碳源的相对重要性。几个A.纤维素分解菌分泌的纤维素分解酶和木聚糖分解酶与来自家族2和3的多个串联排列的碳水化合物结合模块（CBM）融合。在大多数情况下，嗜热模式的基因组和蛋白质组的A。纤维素酶活性较弱，这可能反映了A.纤维素分解菌，因为它从其最接近的系统发育邻居Frankia，嗜温植物内共生体和土壤居民分歧。然而，核糖体蛋白和非编码RNA（rRNA和tRNA）在A.纤维素分解菌表现出嗜热特性，表明细胞翻译机制对环境温度的适应的重要性。IVYWREL氨基酸在A.与嗜温菌相比，解纤维素菌的直系同源物和在第一和第三密码子位置对G和A的反向偏好也表明其正在进行的热适应。在这个纤维素分解，温泉居住的原核生物的基因组中的其他有趣的功能，包括假基因或移动的遗传因素，一个意想不到的补充鞭毛基因的低发生率，和可能的生态生理价值的三个横向收购的基因组岛屿的存在。
We present here the complete 2.4-Mb genome of the cellulolytic actinobacterial thermophile Acidothermus cellulolyticus 11B. New secreted glycoside hydrolases and carbohydrate esterases were identified in the genome, revealing a diverse biomass-degrading enzyme repertoire far greater than previously characterized and elevating the industrial value of this organism. A sizable fraction of these hydrolytic enzymes break down plant cell walls, and the remaining either degrade components in fungal cell walls or metabolize storage carbohydrates such as glycogen and trehalose, implicating the relative importance of these different carbon sources. Several of the A. cellulolyticus secreted cellulolytic and xylanolytic enzymes are fused to multiple tandemly arranged carbohydrate binding modules (CBM), from families 2 and 3. For the most part, thermophilic patterns in the genome and proteome of A. cellulolyticus were weak, which may be reflective of the recent evolutionary history of A. cellulolyticus since its divergence from its closest phylogenetic neighbor Frankia, a mesophilic plant endosymbiont and soil dweller. However, ribosomal proteins and noncoding RNAs ( rRNA and tRNAs) in A. cellulolyticus showed thermophilic traits suggesting the importance of adaptation of cellular translational machinery to environmental temperature. Elevated occurrence of IVYWREL amino acids in A. cellulolyticus orthologs compared to mesophiles and inverse preferences for G and A at the first and third codon positions also point to its ongoing thermoadaptation. Additional interesting features in the genome of this cellulolytic, hot-springs-dwelling prokaryote include a low occurrence of pseudogenes or mobile genetic elements, an unexpected complement of flagellar genes, and the presence of three laterally acquired genomic islands of likely ecophysiological value.