Oligopeptides properties

Table 1. Names and Properties of Selected Brain Oligopeptides...

The minimal cell, as the simplest system which has all the required properties of life (metabolism, self-reproduction and the ability to evolve), is presently studied as part of a new research discipline synthetic biology. This includes subjects such as synthesis in branches of biological systems, for example, of new RNA species, new peptides and new nucleic acid analogues, as well as the synthesis of peptide nucleic acids. One example is the work of M. R. Ghadiri and G. von Kiedrowski on self-replication of oligonucleotides and oligopeptides (Luisi, 2006b). 

Hovgaard, L, and Frokjaer, S. Structure-property model for membrane partitioning of oligopeptides./. Med. Chem. 2000, 43,103-113. 

Some characteristic properties of iron-sulfur clusters in proteins result from interactions with invariant amino acid fragments around the clusters. In particular, clusters in peptide environments exhibit positive shifts in redox potentials relative to those in nonpeptide environments. Such shifts are observed for a variety of oligopeptide model complexes of IFe, 2Fe-2S, and 4Fe-4S proteins. 

Phillips has projected an imaginary oligopeptide with side chains grouped in accordance with their properties to illustrate intricacies of structure and regions of specializing functions. See Fig. 2. 

Fig. 2. Facsimile depiction of an imaginary oligopeptide with side chains grouped in accordance with their properties as proposed by Phillips (1987) in an excellent summary of Protein Engineering in the new and exceptional publication. Scientific Technology Review (The University of Wales). All twenty amino acids are represented as shown by three-letter abbreviations in the boxes on the diagram. Polar, semipolar nonpolar and ionizable portions of the hypothetical oligopeptide are indicated by shaded and dotted areas. Also, note disulfide bridge shown. After Phillips)...

The amino-terminal (N-terminal) residue of a protein can be identified by reacting the protein with a compound that forms a stable covalent link with the free a-amino group, prior to hydrolysis with 6 M HC1. The labeled N-terminal amino acid can then be identified by comparison of its chromatographic properties with standard amino acid derivatives. Commonly used reagents for N-terminal analysis are fluorodinitrobenzene and dansyl chloride. If this technique was applied to the oligopeptide above, the N-terminal residue would be identified as Val, but the remainder of the sequence would still be unknown. Further reaction with dansyl chloride would not reveal the next residue in the sequence since the peptide is totally degraded in the acid hydrolysis step. 

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