aminoacid - phosphorilation (Nov/13/2006 )

what amino acids can be phosphorilate? phenillalaline and ?

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No, Phenylalanine can't be phosphorylated. Serine, threonine and tyrosine are the only ones that can be phosphorylated because they contain an -OH group substituible by a phosphate group. Sometimes residues as histidine and aspartate function as "phosphate acceptors" in some enzymatic reactions, but it's not covalently as in Ser, Thr and Tyr.

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Ok thanks

so in a case of a sequence has a serine phosphorilable, I can mutated to an asp (D) to get a mimic Phosphorilion or to an Alanine (A) to avoide phosphorilation. right?
how does it work? why D mimic phosphorilation and A avoid it?

for exemple if I have a Tyrosine phosphorilation site what mutation can I do to get a mimic phosphorilation or to avoid the phosphorilation.

thanks

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Aspartic acid mimics phosphorylation of serine because it provides the negative charge of -COOH group in the lateral chain that phosphate group also has (i. e. Glutamic acid can mimics phosphorylation because the same reason). Alanine mutation avoid phosphorylation because it doesn't have the -OH group needed for substitution with phosphate group.
To avoid phosphorylation of tyrosine you can mutate to any other residue which lacks -OH group. The best way (thinking in changing only the phorphorylation potential and not the structure of the protein) is change the phosphorylable residue to other with the most similar structure. In case of tyrosine, mutation to phenylalanine is a good choice because it has an aromatic R-group too but it lacks of -OH substituible group.

Regards.

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ok thanks
so for Tyrosine ,an Phe mutant will be accurate to get a none phosphorylation site.
what about to get a mimic phosphorylation. there are no aromatic R-group aa with an extra -Hcoo.

in this case does Asp or Glu will be ok?

thanks

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Yes, Asp or Glu could be right. I think Tyr to Glu is more often used than Asp.

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