Serine dipeptide

Peters, D., and J. Peters. 1982b. Quantum Theory of the Structure and Bonding in Proteins Part 14. The serine dipeptide. J. Mol. Struct. (Theochem) 90, 305-320. 

The synthesis of lanthionines via dehydroalanines has been carried out using an (9,5-di-benzoylated Z-L-Cys-L-Ser-OMe. 31 Using (3-elimination under basic conditions in sodium methoxide and subsequent intramolecular Michael addition, the corresponding L-lanthio-nine derivative was formed. However, as a final step the cyclolanthionyl dipeptide would have to be cleaved at the amide bond to obtain lanthionine. The same authors reported the use of the O-tosylated serine dipeptide which was subjected to (3-elimination, forming the desired dehydroalanine derivative. However, this synthesis also yielded cyclic L-lanthionine dimers as a result of an intermolecular Michael addition. The amounts of cyclolanthionine and lanthionine dimer derivatives depended on the initial concentration of the dipeptides. In addition, the directed synthesis of cyclic lanthionine dimers, which were produced from N-benzyloxycarbonyl-W-trityllanthionine monomethyl ester, has been reported. 32 ... 

Tripeptide A DNP-methionme and 1 mole each of methionine and glycine Tripeptide B DNP-methionme and 1 mole each of methionine and serine Dipeptide C DNP-methionine and 1 mole of methionine Dipeptide D DNP-serine and 1 mole of methionine... 

Note that two dipeptides can result from reaction between alanine and serine, depending on which carboxyl group reacts with which amino group. If the alanine amino group reacts with the serine carboxyl, serylalanine results. 

Give the structural formula of two different dipeptides formed between arginine and serine. 

The primary structure of a polypeptide is its sequence of amino acids. It is customary to write primary structures of polypeptides using the three-letter abbreviation for each amino acid. By convention, the structure is written so that the amino acid on the left bears the terminal amino group of the polypeptide and the amino acid on the right bears the terminal carboxyl group. Figure 13-35 shows the two dipeptides that can be made from glycine and serine. Although they contain the same amino acids, they are different molecules whose chemical and physical properties differ. Example shows how to draw the primary stmcture of a peptide. 

Glycine and serine form two dipeptides, Gly-Ser and Ser-Gly. As the ball-and-stick models show, even dipeptides have distinctive shapes that depend on their primary structure. 

TV-Benzylidene dehydroalanine, however, could not be isolated by this method because the compound decomposed during work up at room temperature.[ 181 CDI was inert toward a series of dipeptides containing a serine residue in the TV-terminal position... 

Scheme 1 Phosphinite derivatives of serine, threonine and tyrosine containing dipeptides 1 R = H, Boc-Phe-Ser(OPPh2)OMe 2 R = Me, Boc-Phe-Thr(OPPh2)OMe 3 R = Ph, Boc-Phe-Tyr(OPPh2)OMe 4R = cyhex, Boc-Phe-Tyr(OPcyhex2)OMe.

In NRPs and hybrid NRP-PK natural products, the heterocycles oxazole and thiazole are derived from serine and cysteine amino acids respectively. For their creation, a cyclization (or Cy) domain is responsible for nucleophilic attack of the side-chain heteroatom within a dipeptide upon the amide carbonyl joining the amino acids [61]. Once the cyclic moiety is formed, the ring may be further oxidized, to form the oxazoline/thiazoline, or reduced, to form oxazolidine/thiazolidine (Figure 13.20). For substituted oxazoles and thiazoles, such as those... 

Siam, K., V. J. Klimkowski, C. Van Alsenoy, J. D. Ewbank, andL. Schafer. 1987. Ab Initio Geometry Refinement of Some Selected Structures of the Model Dipeptide N-Acetyl N -Methyl Serine Amide. J. Mol. Struct. (Theochem) 152, 261-270. 

The unusual amino acid (S)-2-amino-(Z)-3,5-hexadienoic acid (269), which is a component of the toxic y-glutamyl dipeptide isolated from the defensive glands of the Colorado beetle [209], has been synthesized along Scheme 17, after two initial attempts had proved unsuccessful due to the instability of 269 towards various oxidation conditions [210]. Scheme 17 relies on the hydrolysis of an ortho ester to generate the required carboxylic acid. Thus, the L-serine aldehyde equivalent 270 was treated with ( )-l-trimethylsilyl-l-propene-3-boronate to give the addition product 271. Reaction of 271 with KH gave the stereochemically pure (Z)-diene 272. Mild acid treatment of 272 followed by... 

The amino acid components of peptides and proteins are linked together by amide bonds (see p. 60) between a-carboxyl and a-amino groups. This type of bonding is therefore also known as peptide bonding. In the dipeptide shown here, the serine residue has a free ammonium group, while the carboxylate group in alanine is free. Since the amino acid with the free NHs group is named first, the peptide is known as seryl alanine, or in abbreviated form Ser-Ala or SA. 

H N C00R= Alanine, leucine, serine, tyrosine, methionine, proline, etc. Figure 5.5 Synthesis of trifluoroalanine-containing dipeptides. 

The authors applied the same synthetic strategy to racemic 4-alkyl -(iodo-methyl)-2-phenyl-5(4/ )-oxazolones 266 and obtained a diastereomeric mixture of oxazolines 267 and 268 (Scheme 7.86). The diastereoisomers were separated chromatographicaUy and then converted into dipeptides incorporating an a-alkyl-serine residue. ... 

Access to the imino group of oxazolidine-4-carboxylic acid is even more sterically hindered when substitutions are performed at the C2 position. For such cases, the typical procedure is based on the conversion of the desired serine or threonine dipeptides with unprotected hydroxy groups into the oxazolidine rings by reaction with aldehydes or ketones,1139,1691 as described in Vol. E 22a, Section 2.3.2.4. 

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