Bacterial Conjugation: F+ / F+ crosses

[Adrian]

Hi everybody,

I've been reading up on conjugation and came across the concept of surface exclusion, i.e. two specific proteins on the surface of F+ cells preventing another F+ cell's pili from attaching. These to proteins are coded for by the traS and traT genes, both presumably connected to the pilus / plasma bridge / transport mechanism in one way or another.

Now my question is, what exactly do these proteins do? What's theri function, and where exactly are they? Anyone have a URL to a good sketch or other picture of the thing?

Also, are there documented cases of F+ / F+ conjugation occuring nonetheless (albeit with a very low frequency)?

Thanks guys,

[iansmith]

If you can get the following papers, it migth help
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=337311&dopt=Abstract

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6238226&dopt=Abstract

Also, are there documented cases of F+ / F+ conjugation occuring nonetheless (albeit with a very low frequency)?

Recently there been some reports but I don't have the references.

[Adrian]

Wow, thanks for the quick and helpful reply; im starting to like this board [a)]

The abstracts look just like what I've been looking for, I'll go and try to get the papers at the library.