Porphyrin in prebiotic catalysis: Ascertaining a route for the emergence of early metalloporphyrins

Metal ions are known to catalyze certain prebiotic reactions. However, the transition from metal ions to extant metalloenzymes remains unclear. Porphyrins are found ubiquitously in the catalytic core of many ancient metalloenzymes. In this study, we evaluated the influence of porphyrin-based organic scaffold, on the catalysis, emergence and putative molecular evolution of prebiotic metalloporphyrins. We studied the effect of porphyrins on the transition metal ion-mediated oxidation of hydroquinone (HQ). We report a change in the catalytic activity of the metal ions in the presence of porphyrin. This was observed to be facilitated by the coordination between metal ions and porphyrins or by formation of non-coordinated complexes. The metal-porphyrin complexes also oxidized NADH, underscoring its versatility at oxidizing more than one substrate. Our study highlights the selective advantage that some of the metal ions would have had in the presence of porphyrin, underscoring their role in shaping the evolution of protometalloenzymes.

A photo-Responsive Porphyrin-Mn@Choles Complex for Bacteria Treatment

Biocompatible photo-driven producers of singlet oxygen can inhibit the growth of drug-resistant bacteria and tumors. In order to bacteria targeting generator of singlet oxygen for tumor and bacterial treatment, a metal porphyrin liposome (Phy-Mn-Ls) was prepared by the metal coordination reaction and self-assembly of porphyrin compounds with bacteria targeting polymer (HS-PEG-chol). The photo-driven production of 1O2, binding with protein (BSA) and lipase, toxicity to MCF-7 breast cancer cells and inhibitory effect on the growth of Escherichia coli were investigated. Fluorescence analysis results show that Phy-Mn-Ls can bind to lipase, and it shows less effect on the conformation of BSA and is low cytotoxicity without irradiation. In particular, the good biocompatibility made Phy-Mn-Ls exhibit good photosensitive antibacterial activity and anti-tumor properties. The results demonstrate that the coordination of HS-PEG-chol with metal-phorphrin coodination is an effective way to develop bacteria targeting nano-complexes (Phy-Mn-Ls) for lipase affinity and photodriven bacteria treatment.