what is the strongest protein-protein interaction?

*
HI!
Avidin-Biotin interation is strongest known interaction till date. It has affinity constant of femtomolar range, followed by antigen antibody interaction which is of picomolar range on an average.
You can try tagging protein A with Biotin and B with Avidin.It wont interfere with protein function if yours are plant proteins. Biotin is Vit.B2.
hope it helps.

Regards
Shifali
On Sat, 15 Nov 2008 Zhong Silin wrote :


Shifali Chatrath
Graduate Student
Protein science Lab
Dept. of Biological sciences
National University of Singapore
Singapore
+65-65161210
+65-96393449

On Nov 16, 10:48*pm, "shifali chatrath" <[Only registered users see links. ]>
wrote:


Biotin is not a protein, and the OP was looking for an epitope tag to
put on A. I don't know of an easy way to biotinylate one specific
protein during biosynthesis.

Also, vitamin B2 is riboflavin, not biotin.

Nick

--
Nick Theodorakis
[Only registered users see links. ]
contact form:
[Only registered users see links. ]

In article <[Only registered users see links. ]>, Nick Theodorakis <[Only registered users see links. ]> wrote:

Biotinylation tag (a substrate peptide for E.coli biotin ligase) works
quite well in E.coli (over 50% well-expressed protein modified)
but does not work in eukariots. There is always an option to biotinylate
purified protein in vitro using either purchased enzyme or expressing
it yourself (which is easy because it's very soluble). When done right,
in vitro biotynylated of the tagged protein is nearly 100% efficient.

To the OP, I would suggest artificial coiled coils. Basically, a pair of
21 aa peptides used as interacting tags. One is very, very basic,
another is very, very acidic - both conforming to the canonical coiled
coil heptade repeat, so the only coiled coil formed is a heterodimer.
I don't have a ref. but have a xerox somewhere at work. The affinity
of such pair is subnanomolar.

DK

In <3kIUk.8581$[Only registered users see links. ]>,
DK <[Only registered users see links. ]> wrote:


I've used a modified version of the GCN4 leucine zipper for this purpose.
Sadly, I don't have the reference handy - I am at home, but this worked
very well to induce dimerization. If it helps any, the paper that I got
the sequence from was from Peter Kim's lab, and published in Biochemistry.

AC
--
Email: echo 36434455860060025978157675027927670979097959886449 930P | dc