Yennamalli Ragothaman M, Rader Andrew J, Wolt Jeffrey D, Sen Taner Z
Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA.
BMC Struct Biol. 2011 Feb 3;11:10. doi: 10.1186/1472-6807-11-10.
Endoglucanases are usually considered to be synergistically involved in the initial stages of cellulose breakdown-an essential step in the bioprocessing of lignocellulosic plant materials into bioethanol. Despite their economic importance, we currently lack a basic understanding of how some endoglucanases can sustain their ability to function at elevated temperatures required for bioprocessing, while others cannot. In this study, we present a detailed comparative analysis of both thermophilic and mesophilic endoglucanases in order to gain insights into origins of thermostability. We analyzed the sequences and structures for sets of endoglucanase proteins drawn from the Carbohydrate-Active enZymes (CAZy) database.
Our results demonstrate that thermophilic endoglucanases and their mesophilic counterparts differ significantly in their amino acid compositions. Strikingly, these compositional differences are specific to protein folds and enzyme families, and lead to differences in intramolecular interactions in a fold-dependent fashion.
Here, we provide fold-specific guidelines to control thermostability in endoglucanases that will aid in making production of biofuels from plant biomass more efficient.
内切葡聚糖酶通常被认为在纤维素分解的初始阶段协同发挥作用，而纤维素分解是将木质纤维素植物材料生物加工成生物乙醇的关键步骤。尽管它们具有经济重要性，但目前我们对一些内切葡聚糖酶如何能够在生物加工所需的高温下维持其功能，而其他酶却不能，缺乏基本的了解。在本研究中，我们对内切葡聚糖酶进行了详细的比较分析，以便深入了解热稳定性的起源。我们分析了从碳水化合物活性酶（CAZy）数据库中提取的内切葡聚糖酶蛋白序列和结构。
我们的结果表明，嗜热内切葡聚糖酶与其嗜温对应物在氨基酸组成上有显著差异。引人注目的是，这些组成差异特定于蛋白质折叠和酶家族，并以折叠依赖的方式导致分子内相互作用的差异。
在此，我们提供了控制内切葡聚糖酶热稳定性的折叠特异性指导原则，这将有助于提高从植物生物质生产生物燃料的效率。
