Genetically Encoded Fragment-Based Discovery of Glycopeptide Ligands for Carbohydrate-Binding Proteins
作者:Simon Ng、Edith Lin、Pavel I. Kitov、Katrina F. Tjhung、Oksana O. Gerlits、Lu Deng、Brian Kasper、Amika Sood、Beth M. Paschal、Ping Zhang、Chang-Chun Ling、John S. Klassen、Christopher J. Noren、Lara K. Mahal、Robert J. Woods、Leighton Coates、Ratmir Derda
DOI:10.1021/ja511237n
日期:2015.4.29
We describe an approach to accelerate the search for competitive inhibitors for carbohydrate-recognition domains (CRDs). Genetically encoded fragment-based-discovery (GE-FBD) uses selection of phagedisplayed glycopeptides to dock a glycan fragment at the CRD and guide selection of Synergistic peptide motifs adjacent to the CRD. Starting from concanavalin A (ConA), a mannose (Man)-binding protein, as a bait, we narrowed a library of 10(8) glycopeptides to 86 leads that share a consensus motif, Man-WYD. Validation of synthetic leads yielded Man-WYDLF that exhibited 40 50-fold enhancement in affinity over methyl alpha-D-mannopyranoside (MeMan). Lectin array Suggested specificity: Man-WYD derivative bound only to 3 out of 17 proteins-ConA, LcH, and PSA-that bind to Man. An X-ray structure of ConA.:Man-WYD proved that the trimannoside core and Man-WYD exhibit identical CRD docking; but their extra-CRD binding modes are significantly. different. Still, they have comparable affinity and selectivity for various Man-binding proteins. The intriguing observation provides new insight into functional mimicry :of carbohydrates by peptide ligands. GE-FBD may provide an alternative to rapidly search for competitive inhibitors for lectins.