Sequence and structural analysis of the chitinase insertion domain reveals two conserved motifs involved in chitin-binding.
Sequence and structural analysis of the chitinase insertion domain reveals two conserved motifs involved in chitin-binding.
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DOI：
10.1371/journal.pone.0008654
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发表时间：
2010-01-13
期刊：
影响因子：
3.7
通讯作者：
Greene LH
中科院分区：
文献类型：
--
作者：
Li H;Greene LH
几丁质酶广泛存在于生命中，存在于古生菌、细菌、真菌、植物和动物等物种中。它们分解甲壳素，甲壳素是自然界中仅次于纤维素的第二大碳水化合物。因此，它们对于维持碳和氮之间的平衡非常重要，这些碳和氮以不溶性甲壳素的形式被捕获在生物质中。几丁质酶分为两个家族，18个和19个糖苷水解酶。除了一个催化结构域，即磷酸丙糖异构酶桶，许多家族18几丁质酶还含有另一个模块，即几丁质酶插入结构域。虽然许多研究集中在几丁质酶活性中催化结构域的生物学作用，但几丁质酶插入结构域的功能还不完全清楚。生物信息学为理解几丁质酶插入结构域中残基在几丁质酶功能中的作用提供了重要途径。对27个几丁质酶插入结构域序列进行了比对和分析，这些序列包括四个实验确定的结构，跨越五个王国。确定了32个具有保守残基的位置。通过对一些全息酶的结构分析，探索了这些保守残基的作用。氢键和van der Waals计算揭示了四个保守残基的不同子集，组成了两个与寡糖相互作用的序列基序。其他保守残基可能是该结构域的结构、折叠和稳定性的关键。在进化框架内进行的几丁质酶插入结构域的序列和结构研究确定了四个明显与底物相互作用的保守残基。此外，进化研究表明，几丁质酶插入结构域的出现与A亚家族中的家族18几丁质酶的功能之间存在联系。
Chitinases are prevalent in life and are found in species including archaea, bacteria, fungi, plants, and animals. They break down chitin, which is the second most abundant carbohydrate in nature after cellulose. Hence, they are important for maintaining a balance between carbon and nitrogen trapped as insoluble chitin in biomass. Chitinases are classified into two families, 18 and 19 glycoside hydrolases. In addition to a catalytic domain, which is a triosephosphate isomerase barrel, many family 18 chitinases contain another module, i.e., chitinase insertion domain. While numerous studies focus on the biological role of the catalytic domain in chitinase activity, the function of the chitinase insertion domain is not completely understood. Bioinformatics offers an important avenue in which to facilitate understanding the role of residues within the chitinase insertion domain in chitinase function. Twenty-seven chitinase insertion domain sequences, which include four experimentally determined structures and span five kingdoms, were aligned and analyzed using a modified sequence entropy parameter. Thirty-two positions with conserved residues were identified. The role of these conserved residues was explored by conducting a structural analysis of a number of holo-enzymes. Hydrogen bonding and van der Waals calculations revealed a distinct subset of four conserved residues constituting two sequence motifs that interact with oligosaccharides. The other conserved residues may be key to the structure, folding, and stability of this domain. Sequence and structural studies of the chitinase insertion domains conducted within the framework of evolution identified four conserved residues which clearly interact with the substrates. Furthermore, evolutionary studies propose a link between the appearance of the chitinase insertion domain and the function of family 18 chitinases in the subfamily A.
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影响因子：
3.4
作者：
Funkhouser, Jane D.;Aronson, Nathan N., Jr.
通讯作者：
Aronson, Nathan N., Jr.
影响因子：
8
作者：
Hollis, T;Monzingo, AF;Robertus, JD
通讯作者：
Robertus, JD
影响因子：
--
作者：
Hurtado-Guerrero, Ramon;van Aalten, Daan M. F.
通讯作者：
van Aalten, Daan M. F.
影响因子：
2.1
作者：
BRURBERG, MB;EIJSINK, VGH;NES, IF
通讯作者：
NES, IF
影响因子：
5.6
作者：
Bortone, K;Monzingo, AF;Robertus, JD
通讯作者：
Robertus, JD