Designed Self-Assembly of Peptides with G-Quadruplex/Hemin DNAzyme into Nanofibrils Possessing Enzyme-Mimicking Active Sites and Catalytic Functions

Abstract

Enzymes fold into three-dimensional structures to arrange their active groups exquisitely for the remarkable catalytic properties. We are inspired to design and assemble Gln-containing peptides with G-quadruplex DNA/hemin complexes to form the catalytic nanofibrils that possess the horseradish peroxidase-mimicking active sites and catalytic functions. Theoretical simulation results revealed that the intermolecular association of Gln peptide may result in local enrichment and proper orientation of carboxamide groups, which provide potential multivalent hydrogen bonds for enhancing H2O2 affinity to hemin and may behave similarly to distal Arg in a natural heme pocket. The self-folded DNA can provide a guanine base as the axial ligand, and a supramolecular scaffold for supporting and orienting hemin. The β-sheet forming capability of the Q peptides is found to significantly affect the catalytic synergy between the G-DNA and the peptide. The role of hydrogen bonds network provided by self-assembled Gln peptides is illustrated by solvent kinetic isotope effects and H2O2-induced degradation of hemin. The assembly of the Q peptide with G-DNA/hemin DNAzyme also stimulates the chiroselective oxidization of L-DOPA vs D-DOPA. The incorporation of His-containing peptide into the hemin system via self-assembly, which was demonstrated by confocal colocalization images and fluorescence resonance electron transfer results, further enhanced the catalytic activity of the G-DNA/Q peptide/hemin complex. It is hypothesized that the assembly of the triple components allows mimicking the configuration and the function of the catalytic His-Arg-His triad in horseradish peroxidase. Compared to DNA/hemin or peptide/hemin, the catalytic efficiency of the most active complex shows 10-fold enhanced activity. This work opens an avenue to mimic the catalytic residues and their spatial distribution and may provide a primitive enzyme model for the evolution of modern enzymes. Our results may also have implications for the mechanisms of some cell dysfunctions, which are triggered by catalytic aggregation of biomolecules.

Bioinspired Supramolecular Catalysts from Designed Self-Assembly of DNA or Peptides

“…As a step forward, the same group designed β-sheet forming Gln-contained peptides (NH 2 -QQKFQ­FQFEQQ-CONH 2 , Q11) to self-assemble with oligohistidine peptide (NH 2 –HHHHHHHHHH–COOH, H10), G-quadruplex DNA (5′-GGGTA­GGGCGG­GTTGGG-3′, G-DNA) and hemin into catalytic nanofibrils (Figure A) . Theoretical simulation results revealed that the intermolecular association of Gln peptide may result in local enrichment and proper orientation of carboxamide groups, which provided potential multivalent hydrogen bonds for enhancing H 2 O 2 affinity to hemin and may behave similarly to distal Arg (the side chain guanidium can provide up to 5 hydrogen bonds) in a natural heme pocket.…”

A Push–Pull Mechanism Helps Design Highly Competent G-Quadruplex-DNA Catalysts

“…[18][19][20][21] Unfortunately, the performances of G4-DNAzymes are still below those of corresponding enzymes, leading to new research and strategies for improved performance. To date, optimization strategies can be divided into two types: the addition of exogenous activators, [22][23][24][25][26][27][28][29] such as spermine, 22 cytidine triphosphate (CTP), 23 adenine triphosphate (ATP), [23][24][25] templateassembled synthetic G-quartet (TASQ), 26 and self-assembling peptides [27][28][29] on one side, and the modification of the G4 structure [30][31][32][33][34][35] to provide hemin with a more defined and suited binding pocket 31,32 or hemin itself 36,37 on the other side. The latter mostly focuses on the modification of the so-called parallel G4 structure, in which all constitutive DNA strands are codirectionally oriented and the structure displays fairly accessible G-quartets, the privileged hemin-binding site.…”

Self-Assembling Porphyrins as a Single Therapeutic Agent for Synergistic Cancer Therapy: A One Stone Three Birds Strategy

“…Porphyrin molecular self-assembly using cooperative coassembly becomes a popular technique for developing and synthesizing multicomponent photosensitizing materials. ,− Hemin, as a Fe-containing porphyrin, is the U.S. Food and Drug Administration (FDA)-approved drug for acute intermittent porphyria since 1983. , In recent years, hemin has been widely used in the field of catalysis research because of its mimetic peroxidase activity. − Most importantly, hemin possessed three attractive functions in cancer therapy: (1) Fenton catalytic activity, − (2) mimetic peroxidase characteristic that could catalyze H 2 O 2 to generate O 2 , ,, and (3) GSH-depletion capacity. , Thus, based on the well-established evidence, we hypothesized that the hemin-based PS nanomaterial could effectively catalyze endogenous H 2 O 2 to produce O 2 and • OH at the tumor site, thereby enhancing the efficacy of PDT/CDT and simultaneously eliminating the intracellular GSH and inhibiting the activity of GPX4 from inducing ferroptosis. Although some groups used the PDT/CDT/ferroptosis combination therapy approach to obtain successful cancer therapy, , the rational design of hemin-based self-assembly porphyrin nanoparticles that combine all these ideal functions has not been reported to the best of our knowledge.…”