mimicking phosphotyrosine II

[stephan.witte at liai.org]

Sorry, the previous posting has a wrong e-mail adress in the return 
path!
Please respond to THIS poisting, thanks

Hi netters!

I would like to make a constitutive active mutant of a protein which
is activared by tyrosine phosphorylation.

I am thinking of substituting the the tyrosine residue by aspartic
acid. Is aspartic acid mimicking phosphotyrosine?

Are there any references?

Any hint will be appreciated,

thanks,

Stephan