Multiwalled carbon nanotubes (MWCNTs)amphiphilic poly(amidoamine) (PAMAM) dendrimers (APAMAM) based hybrids were developed through individual functionalization of PAMAM with generation 4 (G4) and generation 5 APAMAM (G5) on MWCNTs. The two hybrids were used as matrices and deposited with silver (Ag) nanoparticles (NPs) to develop another two types of new MWCNT based hybrids viz., MWCNTAPAMAM (G...

The ability of the guanine-rich strand of the human mitochondrial DNA (mtDNA) to form G-quadruplex structures (G4s) has been recently highlighted, suggesting potential functions in mtDNA replication initiation and mtDNA stability. G4 structures in mtDNA raise the question of their recognition by factors associated with the mitochondrial nucleoid. The mitochondrial transcription factor A (TFAM),...

Although cisplatin and its analogues have been widely utilized as anticancer metallodrugs in clinics, their serious side effects and damage to normal tissues cannot be avoided because cisplatin kills cancer cells by attacking genomic DNA. Thus the design of metallodrugs possessing different actions of anticancer mechanism is promising. G-quadruplex nucleic acid, which is formed by self-assembly...

G-quadruplex (G4) with stacked G-tetrads structure is able to bind hemin (iron (III)-protoporphyrin IX) to form a unique type of DNAzyme/RNAzyme with peroxidase-mimicking activity, which has been widely employed in multidisciplinary fields. However, its further applications are hampered by its relatively weak activity compared with protein enzymes. Herein, we report a unique intramolecular enha...

Human telomeres and promoter regions of genes fulfill a significant role in cellular aging and cancer. These regions comprise of guanine and cytosine-rich repeats, which under certain conditions can fold into G-quadruplex (G4) and i-motif structures, respectively. Herein, we use UV, circular dichroism and NMR spectroscopy to study several human telomeric sequences and demonstrate that G4/i-moti...

The MYC proto-oncogene is upregulated, often at the transcriptional level, in ∼80% of all cancers. MYC's promoter is governed by a higher order G-quadruplex (G4) structure in the NHE III1 region. Under a variety of conditions, multiple isoforms have been described to form from the first four continuous guanine runs (G41-4) predominating under the physiologically relevant supercoiled conditions....

G-quadruplexes (G4) are nucleic acid conformations of guanine-rich sequences, in which guanines are arranged in the square-planar G-tetrads, stacked on one another. G4 motifs formin vivoand are implicated in regulation of such processes as gene expression and chromosome maintenance. The structure and stability of various G4 topologies were determined experimentally; however, the driving forces ...

In knot concordance three genera arise naturally, g(K), g4(K), and gc(K): these are the classical genus, the 4–ball genus, and the concordance genus, defined to be the minimum genus among all knots concordant to K. Clearly 0 ≤ g4(K) ≤ gc(K) ≤ g(K). Casson and Nakanishi gave examples to show that g4(K) need not equal gc(K). We begin by reviewing and extending their results. For knots representin...

Pif1 family helicases are conserved from bacteria to humans. Here, we report a novel DNA patrolling activity which may underlie Pif1's diverse functions: a Pif1 monomer preferentially anchors itself to a 3'-tailed DNA junction and periodically reel in the 3' tail with a step size of one nucleotide, extruding a loop. This periodic patrolling activity is used to unfold an intramolecular G-quadrup...

The strict human pathogen Neisseria gonorrhoeae can utilize homologous recombination to generate antigenic variability in targets of immune surveillance. To evade the host immune response, N. gonorrhoeae promotes high frequency gene conversion events between many silent pilin copies and the expressed pilin locus (pilE), resulting in the production of variant pilin proteins. Previously, we ident...