Characterization of novel M-superfamily conotoxins with new disulfide linkage
Characterization of novel M-superfamily conotoxins with new disulfide linkage
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DOI：
10.1111/j.1742-4658.2006.05493.x
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发表时间：
2006-11-01
期刊：
影响因子：
5.4
通讯作者：
Chi, Cheng-Wu
中科院分区：
文献类型：
--
作者：
Han, Yu-Hong;Wang, Qi;Chi, Cheng-Wu
具有典型Cys结构（- cc - c - c - cc -）的m超家族是锥螺毒液中发现的7个主要concontoxins超家族之一。根据最后一个Cys环（C4和C5之间）的残基数量，M-超家族concontoxins可以暂时分为四个分支（M-1, M-2, M-3, M-4） [Corpuz GP, Jacobsen RB, Jimenez EC, Watkins M, Walker C, Colledge C, Garrett JE, McDougal O, Li W, Gray WR，等。（2005）生物化学44,8176-8186]。本文报道了从松果中分离到的7种m -超家族松果毒素（其中5种为新发现，2种为mr3a和mr3b）和1种已知的M-1毒素tx3a。此外，我们还从麻果、豹子果和槲皮果中鉴定出6个新的m超家族conoconotoxins cDNA序列。上述新型concontoxins大部分属于M-1和M-2，只有一种属于M-3。对两种M-1型concontoxins mr3e和tx3a的二硫化物分析表明，它们具有不同于M-4支（C1-C4, C2-C5, C3-C6）和M-2支（C1-C6, C2-C4, C3-C5）的新的二硫键排列（C1-C5, C2-C4, C3-C5）。通过比较天然mr3e及其两个区域选择性折叠异构体的HPLC图谱，证实了这种新表征的二硫连通性。这是在具有相同半胱氨酸框架的conotoxins中三种不同模式的二硫连接的第一份报告。
The M-superfamily with the typical Cys framework (-CC-C-C-CC-) is one of the seven major superfamilies of conotoxins found in the venom of cone snails. Based on the number of residues in the last Cys loop (between C4 and C5), M-superfamily conotoxins can be provisionally categorized into four branches (M-1, M-2, M-3, M-4) [Corpuz GP, Jacobsen RB, Jimenez EC, Watkins M, Walker C, Colledge C, Garrett JE, McDougal O, Li W, Gray WR, et al. (2005) Biochemistry44, 8176-8186]. Here we report the purification of seven M-superfamily conotoxins from Conus marmoreus (five are novel and two are known as mr3a and mr3b) and one known M-1 toxin tx3a from Conus textile. In addition, six novel cDNA sequences of M-superfamily conotoxins have been identified from C. marmoreus, Conus leopardus and Conus quercinus. Most of the above novel conotoxins belong to M-1 and M-2 and only one to M-3. The disulfide analyses of two M-1 conotoxins, mr3e and tx3a, revealed that they possess a new disulfide bond arrangement (C1-C5, C2-C4, C3-C6) which is different from those of the M-4 branch (C1-C4, C2-C5, C3-C6) and M-2 branch (C1-C6, C2-C4, C3-C5). This newly characterized disulfide connectivity was confirmed by comparing the HPLC profiles of native mr3e and its two regioselectively folded isoforms. This is the first report of three different patterns of disulfide connectivity in conotoxins with the same cysteine framework.