A novel porphyrin-based molecular probe ZnTCPPSpm4 with catalytic, stabilizing and chiroptical diagnostic power towards DNA B-Z transition

In this work we have designed a new zinc(II) porphyrin with four spermines conjugate in the meso positions, meso-tetrakis-(4-carboxysperminephenyl)porphyrin, ZnTCPPSpm4) with the aim of acting as a chiroptical probe for the Z-form of DNA, a high energy transient conformation of DNA. In addition to monitor by Electronic Circular Dichroism chiroptical response the formation of Z-DNA in the presence of micromolar concentration of spermine, this porphyrin based molecular probe is also able to catalyze and stabilize this important DNA structure. The ZnTCPPSpm4 conjugate represents a perfect example of single molecule, which possesses all these three properties at the same time. The increased stability of Z-DNA in the presence of this derivative opens possibility for further studies on the mechanism of B- to Z-DNA transition, and on the design of new probes with improved efficiency. Exploiting a new zinc porphyrin having four spermines conjugated in the meso positions, to catalyze the B to Z transition in G-C alternated sequence, and obtain a stabilizing and chiroptical probe for Z conformation. [Display omitted] •Zinc(II) porphyrin with four spermines in the meso positions ZnTCPPSpm4 was synthetized.•Cationic ZnTCPPSpm4 porphyrin detects, catalyses and stabilizes Z-DNA.•ZnTCPPSpm4 catalyses the B-Z transition of G-C alternate sequences.•Micromolar concentration of ZnTCPPSpm4 can stabilize the Z-DNA for more than one week.