2-Aminoisobutyric acid (also known as α-aminoisobutyric acid, AIB, α-methylalanine, or 2-methylalanine) is the

non-proteinogenic amino acid In biochemistry, non-coded or non-proteinogenic amino acids are distinct from the 22 proteinogenic amino acids (21 in eukaryotesplus formylmethionine in eukaryotes with prokaryote organelles like mitochondria) which are naturally encoded in the ge ...

with the

structural formula The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are possibly arranged in the real three-dimensional space. The chemical bondi ...

H₂N-C(CH₃)₂-COOH. It is rare in nature, having been only found in meteorites, and some

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

s of

fungal A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...

origin, such as

alamethicin Alamethicin is a channel-forming peptide antibiotic, produced by the fungus ''Trichoderma viride''. It belongs to peptaibol peptides which contain the non-proteinogenic amino acid residue Aib (2-aminoisobutyric acid). This residue strongly indu ...

and some

lantibiotic Lantibiotics are a class of polycyclic peptide antibiotics that contain the characteristic thioether amino acids lanthionine or methyllanthionine, as well as the unsaturated amino acids dehydroalanine, and 2-aminoisobutyric acid. They belong to ...

Synthesis

In the laboratory, 2-aminoisobutyric acid may be prepared from

acetone cyanohydrin Acetone cyanohydrin (ACH) is an organic compound used in the production of methyl methacrylate, the monomer of the transparent plastic polymethyl methacrylate (PMMA), also known as acrylic. It liberates hydrogen cyanide easily, so it is used as a ...

, by reaction with

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

followed by hydrolysis. Industrial scale synthesis can be achieved by the selective

hydroamination In organic chemistry, hydroamination is the addition of an bond of an amine across a carbon-carbon multiple bond of an alkene, alkyne, diene, or allene. In the ideal case, hydroamination is atom economical and green. Amines are common in fine-c ...

methacrylic acid Methacrylic acid, abbreviated MAA, is an organic compound. This colorless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced indu ...

Biological activity

2-Aminoisobutyric acid is not one of the

proteinogenic Proteinogenic amino acids are amino acids that are incorporated biosynthetically into proteins during translation. The word "proteinogenic" means "protein creating". Throughout known life, there are 22 genetically encoded (proteinogenic) amino aci ...

amino acids and is rather rare in nature (''cf.''

non-proteinogenic amino acids In biochemistry, non-coded or non-proteinogenic amino acids are distinct from the 22 proteinogenic amino acids (21 in eukaryotesplus formylmethionine in eukaryotes with prokaryote organelles like mitochondria) which are naturally encoded in the g ...

). It is a strong helix inducer in

peptide Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A ...

s due to

Thorpe–Ingold effect The Thorpe–Ingold effect, gem-dimethyl effect, or angle compression is an effect observed in chemistry where increasing steric hindrance favours ring closure and intramolecular reactions. The effect was first reported by Beesley, Thorpe, and In ...

of its

gem A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, a ...

-di

methyl group In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many ...

. Oligomers of AIB form 3₁₀ helices.

Ribosomal incorporation into peptides

2-Aminoisobutyric acid is compatible with ribosomal elongation of peptide synthesis. Katoh ''et al.'' used

flexizyme An expanded genetic code is an artificially modified genetic code in which one or more specific codons have been re-allocated to encode an amino acid that is not among the 22 common naturally-encoded proteinogenic amino acids. The key prerequisi ...

s and an engineered a tRNA body to enhance the affinity of aminoacylated AIB-tRNA species to

elongation factor P EF-P (elongation factor P) is an essential protein that in bacteria stimulates the formation of the first peptide bonds in protein synthesis. Studies show that EF-P prevents ribosomes from stalling during the synthesis of proteins containing cons ...

. The result was an increased incorporation of AIB into peptides in a cell free translation system. Iqbal ''et al.''. used an alternative approach of creating an editing deficient

valine—tRNA ligase In enzymology, a valine—tRNA ligase () is an enzyme that catalyzes the chemical reaction :ATP + L-valine + tRNAVal \rightleftharpoons AMP + diphosphate + L-valyl-tRNAVal The 3 substrates of this enzyme are ATP, L-valine, and tRNA(Val), wh ...

to synthesize aminoacylated AIB-tRNA^Val. The aminoacylated tRNA was subsequently used in a cell-free translation system to yield AIB-containing peptides.

References

{{DEFAULTSORT:Aminoisobutyric acid, 2- Branched-chain amino acids Amino acids Non-proteinogenic amino acids