question RE: biotin-streptavidin interaction

[radioheadhead]

A little complicated:

I am hooking a 5aa-peptide to biotin for ease of purification, and I need to know how "deep" in the strepavidin binding pocket the biotin moiety rests, i.e. will my pentapeptide be occluded in the binding pocket with the biotin, or will it be exposed? Basically, I am trying to decide how long of a "linker" to add between my pentapeptide of interest and the biotin tag to ensure that the peptide is still accessible outside the streptavidin tetramer.

Thanks!
Toby

[butters]

this link provide the graphical view of the binding in different energy level
[Only registered users see links. ]

[radioheadhead]

thanks so much!