1.Unnatural amino acid mutagenesis of green fluorescent protein.
Wang L1, Xie J, Deniz AA, Schultz PG. J Org Chem. 2003 Jan 10;68(1):174-6.
Unnatural amino acid mutagenesis has been used to selectively substitute tyrosine 66 of green fluorescent protein (GFP) with five novel amino acids: p-amino-L-phenylalanine, p-methoxy-L-phenylalanine, p-iodo-L-phenylalanine, p-bromo-L-phenylalanine, and L-3-(2-naphthyl)alanine. The absorbance and emission maxima of the resulting mutant GFPs span the range from 375 to 435 nm and 428 to 498 nm, respectively. The spectral properties of the mutant GFPs, including the absorbance and fluorescence maxima and quantum yields, correlate with the structural and electronic properties of the substituents on the amino acids.
2.Synthesis of p-amino-L-phenylalanine derivatives with protected p-amino group for preparation of p-azido-L-phenylalanine peptides.
Fahrenholz F, Thierauch KH. Int J Pept Protein Res. 1980 Apr;15(4):323-30.
For the synthesis of p-azidophenylalanine peptides, the p-amino group of p-amino-L-phenylalanine is protected with the Z- or Boc residue via the copper complex or by specific acylation at pH 4.6. The alpha-amino or alpha-carboxy group is blocked by a protecting group (Boc, Ddz, OMe respectively Z, Nps, Ddz), which can be removed selectively. The synthesis of nine derivatives of p-amino-L-phenylalanine for incorporation into the peptide chain is described. The p-amino-phenylalanine is converted to p-azidophenylalanine without affecting disulfide bridges.
3.Biosynthesis of chloramphenicol in Streptomyces sp. 3022a. Identification of p-amino-L-phenylalanine as a product from the action of arylamine synthetase on chorismic acid.
Jones A, Vining LC. Can J Microbiol. 1976 Feb;22(2):237-44.
Products obtained from the action of arylamine synthetase on [G-14C]chorismic acid were fractionated by gel filtration and ion exchange column chromatography to yield a partially purified radioactive component with an arylamine function. From its ultraviolet absorption spectrum and thin-layer chromatographic behaviour the product was considered to be p-aminophenylalanine and the identification was confirmed by co-crystallization with an authentic specimen. Specific deamination of the product with L-amino-acid oxidase indicated that it was the L-epimer. These results strengthen previous evidence that arylamine synthetase is at a branch point in the shikimic acid pathway, specifically diverting intermediates to the synthesis of chloramphenicol.
4.Low-molecular-weight aldehyde inhibitors of cathepsin G.
Lesner A1, Wysocka M, Solek M, Legowska A, Rolka K. Protein Pept Lett. 2009;16(4):408-10.
A series of aldehyde inhibitors with the general formula Ac-Phe-Val-Thr-X-CHO, where X = Lys, Arg, Phe, Tyr, p-nitro-L-phenylalanine (Nif), p-amino-L-phenylalanine (Amf), p-guanidine-L-phenylalanine (Gnf), pyridyl-L-alanine (Pal), was synthesized. The starting structure of this series based on our previous work on cathepsin G chromogenic substrates. The synthesis of all compounds was performed in solid phase applying Fmoc chemistry. We investigated the inhibitory potency of the obtained compounds against cathepsin G and bovine alpha-chymotrypsin and evaluated their dissociation constants (K(i)). The studied peptides displayed different inhibition profiles and potency. As a result, a potent and selective inhibitor of cathepsin G with the sequence Ac-Phe-Val-Thr-Gnf-CHO, displaying K(i) = 22 nM was obtained.
