PNA (Peptide nucleic acid) building blocks refer to the functional substances used for synthesizing PNA.
PNA is a kind of nucleotide analog with polypeptide as the skeleton. It has no charge, strong hybridization specificity, and can resist the degradation of nuclease and protease. It can be seen that it has many advantages, such as its skeleton is electrically neutral, its biological stability is high, and it is easy to combine with DNA or RNA to form a stable complex. Therefore, it can be used as a hybridization probe for disease diagnosis or as an antisense agent for gene therapy exploration.
The chemical structure of PNA itself is relatively simple, so its synthesis method is not cumbersome. It can be seen from the structure that PNA is polymerized from many PNA monomers which formed by PNA building blocks, so the focus of its synthesis is the PNA building blocks. The chemical structure of PNA monomers is similar to that of DNA and RNA. A variety of building blocks are used to synthesize PNA monomers, including the skeleton structure, base and the part connecting base and skeleton. The difference is that the monomers constituting PNA are connected with each other through an unnatural pseudopeptide chain.
The skeleton monomer of classical PNA is N - (2-aminoethyl) glycine, a derivative connecting base on glycine nitrogen Generally, aminoethyl glycine ester with N terminal group protected is synthesized first, and then the base derivative is connected to the unprotected nitrogen.
Since nucleic acid bases, including thymineare, adenine, guanine and cytosine, some of which have active amino groups, they should be protected first so that the alkylation reaction can take place on specific unprotected nitrogen to form corresponding base acetic acid derivatives. The commonly used protective groups are benzyloxycarbonyl and t-butyloxy carbonyl.
With reference to the peptide synthesis method, a suitable condensation agent is used to connect the obtained base acetic acid derivative with the unprotected nitrogen atom on the skeleton.