COMPETENT CELL PREPARATION - (Aug/28/2009 )

I am using CaCl2 for preparation of competent cells in my lab but I have read other protocols also in which MgCl2 is used in place of CaCl2 . Can anyone tell me that which is the better salt for competent cell preparation and also what is the diffrence in their functioning? Also does anyone know the exact reason for adding these salts , all I know is that they bind to the DNA backbone?

When I prepare competent cells I use both: MgCl2 and CaCl2.

I think it all depends on what protocol you use.

What protocol do you use?

And why do you need to use the MgCl2 and CaCl2 , I do not remember the exaxt reason, but I can check it this weekend in one of my textbooks.

pito on Aug 28 2009, 07:04 PM said:

pito on Aug 28 2009, 07:04 PM said:

I use the CaCl2 protocol, but I want to see if using MgCl2 or both CaCl2 n MgCl2 gives better results.

marine on Aug 31 2009, 10:44 AM said:

Do you have protocols that involve the use of both MgCl2 and CaCl2 ? If not, I can give you the protocol I use.

And how do you know your protocol is not good?

I used Cacl2 to prepare competent cells. I think the Cacl2 protocal can give us a good result and there is no need to prepare competent cells using Mgcl2.

My experience with CaCl2 alone is very good. Never tried anything else. The important thing in my experience is using FRESH cells. If you prepare them the same day, which is pretty simple, they (BL21) transform brilliantly!