MIDMAT 1 substitution matrix.

MIDMAT 1 substitution matrix values are calculated based on basin statistics derived from the rotor combinations of amino acids in the structural dataset of 22,997 non-redundant structures from PISCES server. The amino acids are represented as their single letter codes.MIDMAT 1替换矩阵（MIDMAT 1 substitution matrix）的分值基于从PISCES服务器（PISCES server）获取的22997条非冗余蛋白质结构数据集中，由氨基酸转子组合推导得到的构象盆地统计量计算所得。氨基酸以单字母代码形式表征。