Deciphering structural and functional roles of disulfide bonds in decorsin  

作　　者：WU LingZhi LI Ying YANG Yang QIN Meng 

机构地区：[1]School of Geography and Biological Information, Nanjing University of Posts and Telecommunications [2]National Laboratory of Solid State Microstructure and Department of Physics, Nanjing University [3]Department of Chemistry, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology

出　　处：《Science China Chemistry》2013年第10期1485-1492,共8页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(91127026,11074115 and 61101056);the Open Project of State Key Laboratory of Bioelectronics of Southeast University(2011E14);supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions

摘　　要：Decorsin, an antagonist of integrin glycoprotein IIb/IIIa, contains Arg-Gly-Asp （RGD） sequence and three disulfide bridges. The function of RGD sequence has already been well defined, but the roles of conserved disulfide bonds in antihemostatic proteins still remain unclear. Herein we use the fusion expression and characterization of mutant decorsin to study the func- tions of disulfide bonds in protein structure, stability and biological activity. The purified protein shows an apparent inhibition of activity to platelet aggregation induced by ADP with IC50 of 500 nM. The removal of cys7-cysl5 （from cysteine to serine） at the N-terminal causes a thirty-fold decrease of the inhibition activity with IC50 of 15 ~tM, whereas the mutation of cys22-cys38 at the C-terminal completely impairs the biological activity of decorsin. The overall secondary and tertiary struc- tures of decorsin are disrupted inevitably without disulfide bonds. Using a domain insertion mutation, the retaining of RGD loop and the adjacent disulfide bond produces a week antihemostatic activity of decorsin. This reveals that the overall structure of decorsin stabilized by the three conserved disulfide bridges is cooperative for antihemostatic function. Our study on the ef- fect of disulfide bonds together with RGD-sequence on the protein function is helpful for structure-based drug design of an- tithrombotic research.Decorsin,an antagonist of integrin glycoprotein IIb/IIIa,contains Arg-Gly-Asp(RGD)sequence and three disulfide bridges.The function of RGD sequence has already been well defined,but the roles of conserved disulfide bonds in antihemostatic proteins still remain unclear.Herein we use the fusion expression and characterization of mutant decorsin to study the functions of disulfide bonds in protein structure,stability and biological activity.The purified protein shows an apparent inhibition of activity to platelet aggregation induced by ADP with IC50 of 500 nM.The removal of cys7-cys15(from cysteine to serine)at the N-terminal causes a thirty-fold decrease of the inhibition activity with IC50 of 15 M,whereas the mutation of cys22-cys38 at the C-terminal completely impairs the biological activity of decorsin.The overall secondary and tertiary structures of decorsin are disrupted inevitably without disulfide bonds.Using a domain insertion mutation,the retaining of RGD loop and the adjacent disulfide bond produces a week antihemostatic activity of decorsin.This reveals that the overall structure of decorsin stabilized by the three conserved disulfide bridges is cooperative for antihemostatic function.Our study on the effect of disulfide bonds together with RGD-sequence on the protein function is helpful for structure-based drug design of antithrombotic research.

关 键 词：antihemostatic activity decorsin disulfide bonds DISINTEGRINS platelet aggregation inhibitor RGD-sequence 

分 类 号：Q51[生物学—生物化学]