Sage-Tips

Is serine a conservative substitution for threonine?

Conservative substitution: The replacement of an amino acid residue in one protein by one with similar chemical properties in another protein. For example, the replacement of serine by threonine, or leucine by isoleucine, are both considered conservative substitutions.

Which amino acid is commonly used as a substitution for threonine to prevent phosphorylation in studies of protein phosphorylation?

There are no natural amino acid side chains that provide the combination of negative charge with a tetrahedral center. However, there are numerous studies showing partial phenotypes when aspartic acid is substituted for phospho-serine or glutamic acid is substituted for phospho-threonine [39,57].

What is the most substituted amino acid?

According to Grantham’s distance, most similar amino acids are leucine and isoleucine and the most distant are cysteine and tryptophan.

Which two amino acids can be used to mimic a phosphorylated amino acid?

Phosphomimetics are amino acid substitutions that mimic a phosphorylated protein, thereby activating (or deactivating) the protein. Within cells, proteins are commonly modified at serine, tyrosine and threonine amino acids by adding a phosphate group.

Which residue is best for phenylalanine replacement?

Substitutions: As Phenylalanine is an aromatic, hydrophobic, amino acid, it prefers substitution with other amino acids of the same type (see above). It particularly prefers to exchange with Tyrosine, which differs only in that it contains a hydroxyl group in place of the ortho hyddrogen on the benzene ring.

What can replace serine?

Threonine
Note that in this context, Serine can often be replaced by Threonine, but is unlikely to be replaced by Tyrosine, as the enzymes that catalyse the reactions (i.e. the protein kinases) are highly specific (i.e. Tyrosine kinases generally do not work on Serines/Threonines and vice versa).

How is serine phosphorylated?

Phosphorylation on amino acids, such as serine, threonine, and tyrosine results in the formation of a phosphoprotein, when the phosphate group of the phosphoprotein reacts with the -OH group of a Ser, Thr, or Tyr sidechain in an esterification reaction.

What type of amino acid is threonine?

Threonine, an essential amino acid, is a hydrophilic molecule. Threonine is an other hydroxyl-containing amino acid. It differs from serine by having a methyl substituent in place of one of the hydrogens on the β carbon and it differs from valine by replacement of a methyl substituent with a hydroxyl group.

Can you phosphorylate alanine?

Serine is often mutated to glutamic acid (sometimes aspartic acid) to mimic phosphorylation of the serine residue. Conversely, mutating serine to alanine prevents potential phosphorylation. Phosphorylation occurs after the protein has folded into its correct conformation.

Can serine form hydrogen bonds?

Serine and threonine possess hydroxyl groups in their side chains and as these polar groups are close to the main chain they can form hydrogen bonds with it.