Supramolecular multiplexes from collagen mimetic peptide-PNA(GGG) conjugates and C-rich DNA: pH-induced reversible switching from triplex-duplex to triplex--motif.

Peptides are well known for forming nanoparticles, while DNA duplexes, triplexes and tetraplexes create rigid nanostructures. Accordingly, the covalent conjugation of peptides to DNA/RNA produces hybrid self-assembling features and may lead to interesting nano-assemblies distinct from those of their individual components. Herein, we report the preparation of a collagen mimetic peptide incorporating lysine in its backbone, with alkylamino side chains radially conjugated with G-rich PNA [collagen-(PNA-GGG)].

Supramolecular polyplexes from Janus peptide nucleic acids (bm-PNA-G5): self-assembled bm-PNA G-quadruplex and its tetraduplex with DNA.

Nucleic acids (DNA and RNA) can form diverse secondary structures ranging from hairpins to duplex, triplex, G4-tetraplex and C4-i-motifs. Many of the DNA analogues designed as antisense oligonucleotides (ASO) are also adept at embracing such folded structures, although to different extents with altered stabilities. One such analogue, peptide nucleic acid (PNA), which is uncharged and achiral, forms hybrids with complementary DNA/RNA with greater stability and specificity than DNA:DNA/RNA hybrids.

Dynamics of terminal fraying-peeling and hydrogen bonds dictates the sequential . cooperative melting pathways of nanoscale DNA and PNA triplexes.

Peptide nucleic acids (PNAs) are charge-neutral synthetic DNA/RNA analogues. In many aspects of biology and biotechnology, the details of DNA and PNA melting reaction coordinates are crucial, and their associative/dissociative details remain inadequately understood. In the current study, we have attempted to gain insights into comparative melting pathways and binding affinity of iso-sequences of an 18-mer PNA-DNA-PNA triplex and the analogous DNA-DNA-DNA triplex, and DNA-DNA and PNA-DNA duplexes.

Gemdimethyl Peptide Nucleic Acids (α/β/γ-PNA): E/Z-Rotamers Influence the Selectivity in the Formation of Parallel/Antiparallel -PNA:DNA/RNA Duplexes.

Peptide nucleic acids (PNAs) consist of an aminoethylglycine () backbone to which the nucleobases are linked through a tertiary amide group and bind to complementary DNA/RNA in a sequence-specific manner. The flexible backbone has been the target for several chemical modifications of the PNA to improve its properties such as specificity, solubility, etc. PNA monomers exhibit a mixture of two rotamers (Z/E) arising from the restricted rotation around the tertiary amide N-CO bond.

Aza-PNA: Engineering E-Rotamer Selectivity Directed by Intramolecular H-bonding.

The replacement of α(CH) by NH in monomers of standard PNA and its homologue β- PNA leads to respective -PNA monomers ( and ) in which the NH can form either an 8-membered H-bonded ring with folding of the backbone (DMSO and water) or a 5-membered NH─αCO (water) to stabilize -type rotamers. Such -PNA oligomers with exclusive rotamers and intraresidue backbone H-bonding can modulate its DNA/RNA binding and assembling properties.

: 2022 Spring Forward, 2021 Look Back .

has entered its seventh year of publishing since the journal was launched in 2016. We are pleased to present an update and summarize 's new plans and offerings in 2022 and look back and share the key journal statistics from 2021 while featuring some of its excellent published content. We take this opportunity to thank our global pool of reviewers for their continued voluntary and invaluable support in serving the journal and their assistance in maintaining the quality of our published content.

Silver soldering of PNA:DNA duplexes: assembly of a triple duplex from bimodal PNAs with all-C on one face.

DNA:bm-PNA duplexes endowed with all-C on either the t-amide or triazole face and mixed base sequence on the other face can be welded with silver ions through C:Ag:C connects to give triple duplexes in one complex. The interplay of WC and Ag-mediated duplexes leads to synergistic stability effects on both duplexes and the complex.

Molecular Assembly of Triplex of Duplexes from Homothyminyl-Homocytosinyl Cγ(/)-Bimodal Peptide Nucleic Acids with dA/dG and the Cell Permeability of Bimodal Peptide Nucleic Acids.

Peptide nucleic acids (PNAs) are analogues of DNA with a neutral acyclic polyamide backbone containing nucleobases attached through a t-amide link on repeating units of aminoethylglycine (). They bind to complementary DNA or RNA in a sequence-specific manner to form duplexes with higher stablity than DNA:DNA and DNA:RNA hybrids. We have recently explored a new type of PNA termed bimodal PNA (-PNA) designed with two nucleobases per repeating unit of PNA oligomer and attached at Cα or Cγ of each unit through a spacer sidechain.

Peptide Nucleic Acid with Double Face: Homothymine-Homocytosine Bimodal Cα-PNA (-Cα-PNA) Forms a Double Duplex of the -PNA:DNA Triplex.

Cα-bimodal peptide nucleic acids (-Cα-PNA) are PNAs with two faces and are designed homologues of PNAs in which each aminoethylglycine () repeating unit in the standard PNA backbone hosts a second nucleobase at Cα through a spacer chain with a triazole linker. Such -Cα-PNA with mixed sequences can form double duplexes by simultaneous binding to two complementary DNAs, one to the base sequence on t-amide side and the other to the bases on the Cα side chain. The synthesis of -Cα-PNA with homothymine (T) on the t-amide face and homocytosine (C) on the Cα side chain through the triazole linker was achieved by solid phase synthesis with the global click reaction.

Silver assisted stereo-directed assembly of branched peptide nucleic acids into four-point nanostars.

Branched chiral peptide nucleic acids br(4S/R)-PNA with three arms of PNA-C4 strands were constructed on a central chiral core of 4(R/S)-aminoproline as the branching center. The addition of Ag+ triggered the self-assembly of branched PNAs through the formation of C-Ag+-C metallo base pairing of the three PNA C4 arms leading to non-covalent dendrimers, whose architecture is directed by the C4(R/S)-stereocenter of core 4-aminoproline. The 4S-aminoprolyl core enabled the precise formation of four-pointed nanostars that was not realised with 4R-aminoprolyl or acyclic, achiral aminoethyl glycyl PNA cores.

Cγ(/)-Bimodal Peptide Nucleic Acids (Cγ--PNA) Form Coupled Double Duplexes by Synchronous Binding to Two Complementary DNA Strands.

Peptide nucleic acids (PNAs) are linear equivalents of DNA with a neutral acyclic polyamide backbone that has nucleobases attached via -amide link on repeating units of aminoethylglycine. They bind complementary DNA or RNA with sequence specificity to form hybrids that are more stable than the corresponding DNA/RNA self-duplexes. A new type of PNA termed bimodal PNA [Cγ(/)--PNA] is designed to have a second nucleobase attached via amide spacer to a side chain at Cγ on the repeating units of PNA oligomer.

Conformation and Morphology of 4-(NH/OH)-Substituted l/d-Prolyl Polypeptides: Effect of Homo- and Heterochiral Backbones on Formation of β-Structures and Nanofibers.

The relative stereochemistry of C2 and C4 in 4-substituted prolyl polypeptides plays an important role in defining the derived conformation in solution. -(2,4)-Amino/hydroxy-l-prolyl polypeptide (l- /l- ) shows a PPII conformation in phosphate buffer and a β-structure in a relatively hydrophobic solvent, trifluoroethanol (TFE). It is now demonstrated that the homochiral enantiomeric cis-substituted d-prolyl polypeptide (d- /d- ) exhibits mirror image β-structures in TFE.