Centre de Recherche sur les Macromolécules Végétales (CERMAV)-CNRS, Université Joseph Fourier and Institut de Chimie Moléculaire de Grenoble, 38041 Grenoble, France.
J Biol Chem. 2012 Feb 3;287(6):4335-47. doi: 10.1074/jbc.M111.314831. Epub 2011 Dec 14.
Burkholderia ambifaria is generally associated with the rhizosphere of plants where it has biocontrol effects on other microorganisms. It is also a member of the Burkholderia cepacia complex, a group of closely related bacteria that cause lung infections in immunocompromised patients as well as in patients with granulomatous disease or cystic fibrosis. Our previous work indicated that fucose on human epithelia is a frequent target for lectins and adhesins of lung pathogens (Sulák, O., Cioci, G., Lameignère, E., Balloy, V., Round, A., Gutsche, I., Malinovská, L., Chignard, M., Kosma, P., Aubert, D. F., Marolda, C. L., Valvano, M. A., Wimmerová, M., and Imberty, A. (2011) PLoS Pathog. 7, e1002238). Analysis of the B. ambifaria genome identified BambL as a putative fucose-binding lectin. The 87-amino acid protein was produced recombinantly and demonstrated to bind to fucosylated oligosaccharides with a preference for αFuc1-2Gal epitopes. Crystal structures revealed that it associates as a trimer with two fucose-binding sites per monomer. The overall fold is a six-bladed β-propeller formed by oligomerization as in the Ralstonia solanacearum lectin and not by sequential domains like the fungal fucose lectin from Aleuria aurantia. The affinity of BambL for small fucosylated glycans is very high as demonstrated by microcalorimetry (K(D) < 1 μM). Plant cell wall oligosaccharides and human histo-blood group oligosaccharides H-type 2 and Lewis Y are bound with equivalent efficiency. Binding to artificial glycosphingolipid-containing vesicles, human saliva, and lung tissues confirmed that BambL could recognize a wide spectrum of fucosylated epitopes, albeit with a lower affinity for biological material from nonsecretor individuals.
生黄伯克霍尔德氏菌通常与植物的根际相关,在那里它对其他微生物具有生物防治作用。它也是洋葱伯克霍尔德氏菌复合体的成员,这是一组密切相关的细菌,会导致免疫功能低下的患者以及患有肉芽肿病或囊性纤维化的患者肺部感染。我们之前的工作表明,人上皮细胞上的岩藻糖是肺部病原体凝集素和黏附素的常见靶标(Sulák,O.,Cioci,G.,Lameignère,E.,Balloy,V.,Round,A.,Gutsche,I.,Malinovská,L.,Chignard,M.,Kosma,P.,Aubert,D. F.,Marolda,C. L.,Valvano,M. A.,Wimmerová,M.,和 Imberty,A.(2011)PLoS Pathog. 7,e1002238)。生黄伯克霍尔德氏菌基因组的分析表明 BambL 是一种潜在的岩藻糖结合凝集素。该 87 个氨基酸的蛋白质是通过重组产生的,并证明其与岩藻糖基化寡糖结合具有对 αFuc1-2Gal 表位的偏好。晶体结构表明,它以三聚体的形式与每个单体的两个岩藻糖结合位点结合。整体折叠是一个六叶β-推进器,通过聚合形成,就像茄科雷尔氏菌凝集素一样,而不是像真菌 Aleuria aurantia 的岩藻糖凝集素那样通过连续的结构域形成。BambL 对小岩藻糖基化糖的亲和力非常高,如微量热法所证明的(K(D) < 1 μM)。植物细胞壁寡糖和人组织血型 2 型和 Lewis Y 型的组氨酸-血液组寡糖以等效的效率结合。与人工糖脂包被的囊泡、人唾液和肺组织的结合证实 BambL 可以识别广泛的岩藻糖基化表位,尽管对非分泌个体的生物材料的亲和力较低。