Previous studies have indicated that each conotoxin precursor has a hyperconserved signal region, a rather conserved pro region and a hypervariable mature region, and nucleotide mutations are the main driven factor. However, in this study, we made an in-depth analysis on the M-superfamily conotoxin precursors and found that the diversity of the signal, pro and mature regions are more complicated than previous findings. Different conotoxin precursors can have same signal, pro and/or mature regions, especially different conotoxin precursors with same mature region but different signal and pro regions. In addition, insertions and deletions (indels) were detected in conotoxin precursors. Indels are infrequent in the signal region but frequent in the pro and mature regions. In contrast to deletions that dominate in the pro region, insertions dominate in the mature region. The number of amino acids is crucial for the physiological functions of mature conotoxins, therefore indels, especially insertions in the mature region, play an important role in the sequence and function diversity of conotoxins.

中文翻译：

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插入和删除在芋螺毒素的多样性中起重要作用。

先前的研究表明，每种芋螺毒素前体均具有一个高度保守的信号区，一个相对保守的前区和一个高度可变的成熟区，核苷酸突变是主要驱动因素。然而，在这项研究中，我们对M超家族芋螺毒素前体进行了深入分析，发现信号，亲和成熟区域的多样性比以前的发现更为复杂。不同的芋螺毒素前体可以具有相同的信号区，前和/或成熟区，特别是具有相同的成熟区但具有不同的信号毒素和前区的不同螺毒素前体。此外，在芋螺毒素前体中检测到插入和缺失（indels）。插入缺失在信号区域中很少见，但在亲和成熟区域中很常见。与在亲区域中占主导地位的删除相比，插入在成熟区域占主导。氨基酸的数目对于成熟芋螺毒素的生理功能至关重要，因此插入缺失，特别是在成熟区域的插入，在芋螺毒素的序列和功能多样性中起着重要作用。