co-IP of bacteria membrane protein

Hi, all

I am planning to do a co-IP on an inner membrane protein with HA tag of
Caulobacter(a gram negative bacterium), and I am hoping to pull down some
protein complexes under non-denaturing condition (low detergent). Has
anybody done similar experiments like this? I really don't know where to
start, does anybody have a protocol for that?

How shall I determine the right condition that can solubilize the membrane
protein yet maintain the complexes? For HA tag, which antibody will be
better, monoclonal or polyclonal?

Thank you very much! Suggestion will be really appreciated!