一-一一上一一一 (3)极性R基团带负电荷氨基酸：2个 Asp GIu (4)极性R基团带正电荷氨基酸：3个 His Lys Arg （3）极性R基团带负电荷氨基酸：2个 Asp Glu （4）极性R基团带正电荷氨基酸：3个 His Lys Arg