Structural basis of the affinity for oligomannosides and analogs displayed by BC2L-A, a Burkholderia cenocepacia soluble lectin
Structural basis of the affinity for oligomannosides and analogs displayed by BC2L-A, a Burkholderia cenocepacia soluble lectin
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DOI：
10.1093/glycob/cwp151
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发表时间：
2010-01-01
期刊：
影响因子：
4.3
通讯作者：
Imberty, Anne
中科院分区：
文献类型：
--
作者：
Lameignere, Emilie;Shiao, Tze Chieh;Imberty, Anne
新洋葱伯克霍尔德氏菌是一种条件致病菌，含有三种可溶性糖结合蛋白，与铜绿假单胞菌的岩藻糖结合凝集素PA-IIL相关。所有蛋白质都含有PA-IIL样结构域，其中两个蛋白质还含有一个额外的N末端结构域，该结构域与已知蛋白质没有序列相似性。对最短的阵列B进行印刷阵列筛选。cenocepacia凝集素A（BC 2L-A），证明了对寡甘露糖型N-聚糖结构的严格特异性（Lameignere E，Malinovska L，Slavikova M，Duchaud E，Mitchell EP，Varrot A，Sedo O，Imberty A，Wimmerova M. 2008.条件致病菌新洋葱伯克霍尔德氏菌凝集素识别甘露糖的结构基础。411：307-318）。通过滴定微量热法测试二糖α Man 1 - 2 Man、α Man 1 - 3 Man和α Man 1 - 6 Man以及三糖α Man 1 -3（α Man 1 -6）Man，以评价它们在溶液中对BC 2L-A的亲和力并表征结合的热力学。还测试了呈现由柔性或刚性间隔区分开的两个甘露糖苷残基的寡聚甘露糖类似物。只有刚性的产量高亲和力结合与快速动力学的聚类，而灵活的类似物和三甘露糖苷显示中等的亲和力，在短时间尺度上没有聚类效果。BC 2L-A的晶体结构是在与α Man 1 - 3 Man二糖和α Man 1（α Man 1 -6）-3Man三糖的复合物中获得的。与三糖共结晶所需的漫长时间允许簇的形成，因为在以1.1埃分辨率溶解的BC 2L-A-三甘露糖复合物中，糖在两个相邻的二聚体之间产生桥，产生分子串。进行AFM实验，以便可视化通过这种类型的相互作用在溶液中形成的细丝。
The opportunistic pathogen Burkholderia cenocepacia contains three soluble carbohydrate-binding proteins, related to the fucose-binding lectin PA-IIL from Pseudomonas aeruginosa. All contain a PA-IIL-like domain and two of them have an additional N-terminal domain that displays no sequence similarities with known proteins. Printed arrays screening performed on the shortest one, B. cenocepacia lectin A (BC2L-A), demonstrated the strict specificity for oligomannose-type N-glycan structures (Lameignere E, Malinovska L, Slavikova M, Duchaud E, Mitchell EP, Varrot A, Sedo O, Imberty A, Wimmerova M. 2008. Structural basis for mannose recognition by a lectin from opportunistic bacteria Burkholderia cenocepacia. Biochem J. 411:307-318.). The disaccharides alpha Man1-2Man, alpha Man1-3Man, and alpha Man1-6Man and the trisaccharide alpha Man1-3(alpha Man1-6)Man were tested by titration microcalorimetry in order to evaluate their affinity for BC2L-A in solution and to characterize the thermodynamics of the binding. Oligomannose analogs presenting two mannoside residues separated by either flexible or rigid spacer were also tested. Only the rigid one yields to high affinity binding with a fast kinetics of clustering, while the flexible analog and the trimannoside display moderate affinities and no clustering effect on short time scale. The crystal structures of BC2L-A have been obtained in complex with alpha Man1-3Man disaccharide and alpha Man1(alpha Man1-6)-3Man trisaccharide. The lengthy time required for the co-crystallization with the trisaccharide allowed for the formation of cluster since in the BC2L-A-trimannose complex solved at 1.1 angstrom resolution, the sugar creates a bridge between two adjacent dimers, yielding to molecular strings. AFM experiments were performed in order to visualize the filaments formed in solution by this type of interaction.