Could tell me the mechanism of SDS - (May/30/2002 )

When I do colony screening,the function of SDS is to lysis the bacterial cell wall.When at the hybridization step,why the hybridization buffer is added with 0.1%SDS?And the washing buffer also add SDS.Why?Could anyone tell me why the SDS have multiple functions.Thanks!

SDS is a strong cationic detergent. THe DNA in your hybridization has a net negative charge. The idea is to reduce non-specific binding of your probe to non-target DNA and the membrane itself. The more SDS in your hybridization the more stringent the conditions, and less likely to bind nonspecific sequences. On the other hand you also use SSC (sodium citrate, sodium chloride) this encourages binding to nucleic acids at higher concentrations. In the buffer you create a balance between binding your target and not binding anything else. I hope this helps.

Rio,
I'm sorry. It seems that SDS is an anionic detergent so the interaction I described is incorrect. Perhaps the interaction is dependent upon lowerering the surface tension of water. The rest of the information is correct.
Joe