bash sort from the end of string

I want to sort file by first file, but the last character is the most important.

For example form file:

"AAAACTTTTT"                    1       2

"AAAACAAAAA"    1       2       6       4

To:

"AAAACAAAAA"    1       2       6       4

"AAAACTTTTT"                    1       2

I tried:

sort -k1,1 file

Of course it doesn't work, but I have no idea how I can do this. Could you help me? Mayby some secret flags?