WHY? HOW CAN I DO?

   No matter how carefully I prepared it, and no matter how seriously I implemented the plan, I am unluckily to  encounter something unexpected and unwelcome. What's the reason? How can I overcome the difficulty? The experiment will drive me crazy!

  According to Murphy's law, anything that can go wrong will go wrong.  However, another man had really succeeded already 10 years ago. Is there something wrong with the plasmid pet21α, or the E.coli BL21 plys S DE3? I should take some efforts to get the reason.

  Test the sequence of the plasmid, and buy a new E.coli BL21 from the company!

   Crazy! Crazy! Crazy! I'M GOING CRAZY!