tailieunhanh - Báo cáo khoa học: Solution structure of an M-1 conotoxin with a novel disulfide linkage

The M-superfamily of conotoxins has a typical Cys framework (-CC-C-C-CC-), and is one of the eight major superfamilies found in the venom of the cone snail. Depending on the number of residues located in the last Cys loop (between Cys4 and Cys5), the M-superfamily family can be divi-ded into four branches, | ễFEBS Journal Solution structure of an M-1 conotoxin with a novel disulfide linkage Wei-Hong Du1 2 Yu-Hong Han3 4 Fei-juan Huang1 Juan Li2 Cheng-Wu Chi3 4 J and Wei-Hai Fang2 1 Department of Chemistry Renmin University of China Beijing China 2 Department of Chemistry Beijing NormalUniversity China 3 Institute of Biochemistry and Cell Biology Shanghai Institutes for BiologicalSciences Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences Shanghai China 4 Institute of Protein Research Tongji University Shanghai China Keywords disulfide linkage M-conotoxin mr3e NMR solution structure Correspondence . Fang Department of Chemistry Beijing NormalUniversity 19 Xin Jie Kou Wai St. Beijing 100875 China Fax 86 10 5880 2075 Tel 86 10 5880 5382 E-mail fangwh@ . Chi Shanghai Institute of Biochemistry and Cell Biology Chinese Academy of Sciences 320 YueYang Road Shanghai 200031 China Fax 86 21 5492 1011 Tel 86 21 5492 1165 E-mail chi@ These authors contributed equally to this study Received 10 December 2006 revised 7 March 2007 accepted 16 March 2007 doi The M-superfamily of conotoxins has a typical Cys framework -CC-C-C-CC- and is one of the eight major superfamilies found in the venom of the cone snail. Depending on the number of residues located in the last Cys loop between Cys4 and Cys5 the M-superfamily family can be divided into four branches namely M-1 -2 -3 and -4. Recently two M-1 branch conotoxins mr3e and tx3a have been reported to possess a new disulfide bond arrangement between Cys1 and Cys5 Cys2 and Cys4 and Cys3 and Cys6 which is different from those seen in the M-2 and M-4 branches. Here we report the 3D structure of mr3e determined by 2D 1H NMR in aqueous solution. Twenty converged structures of this peptide were obtained on the basis of 190 distance constraints obtained from NOE connectivities as well as six u dihedral angle three hydrogen bond and three disulfide bond .