It facilitatesribosomal binding and therefore, protein synthesis.

The cationic porphyrin 5,10,15,20-tetra-(N-methyl-4-pyridyl)porphyrin (TMPyP4) binds to quadruplex DNA and is thereby an inhibitor of human telomerase (Wheelhouse et al. J. Am. Chem. Soc. 1998, 120, 3261-3262). Herein the synthesis and telomerase-inhibiting activity of a wide range of analogues of TMPyP4 are reported, from which rules for a structure-activity relationship (SAR) have been discerned: (1) stacking interactions are critical for telomerase inhibition, (2) positively charged substituents are important but may be interchanged and combined with hydrogen-bonding groups, and (3) substitution is tolerated only on the meso positions of the porphyrin ring, and the bulk of the substituents should be matched to the width of the grooves in which they putatively lie. This SAR is consistent with a model presented for the complexation of TMPyP4 with human telomeric quadruplex DNA.

DNA Synthesis | Dna Replication | Telomere

The 5' cap present on all eukaryoticmRNAs seems to be the first signal to start protein synthesis.

DNA replication & telomerase Flashcards | Quizlet

During DNA replication, theyfacilitate the untwisting of supertwisted DNA (see also and ).

Telomerase Function | Telomere | Dna

We report that introduction of the hTERT gene into human diploid fibroblasts results in emergence of telomerase activity in these cells and the ability to induce the reactivation of DNA synthesis in the macrophage nuclei in heterokaryons.

What is the role in telomerase in DNA replication and …

Telomerase is an RNA-dependent DNA polymerase (reverse transcriptase) specialized in the synthesis of short DNA repeats onto chromosome ends, a function essential for chromosome stability and cellular immortality in eukaryotes. Unlike conventional polymerases, telomerase is a ribonucleoprotein (RNP) enzyme, minimally composed of the catalytic telomerase reverse transcriptase (TERT) and the telomerase RNA (TR) subunit. While the TERT catalytic core is well conserved and shares several motifs with conventional reverse transcriptases, the TR subunit is highly divergent and has evolved species-specific structural elements essential for telomerase RNP assembly and biogenesis. Telomerase is unique among polymerases, capable of producing a DNA product vastly longer than the RNA template. This unique polymerization reaction relies on repeatedly regenerating and reusing the short TR template during DNA synthesis, producing the characteristic repetitive telomeric DNA sequence. Processive telomeric repeat synthesis is dependent on “template translocation” for template regeneration, a complex mechanism that is only partially understood. Correspondingly, telomerase-specific domains within telomerase TERT-TR core function cooperatively with telomerase accessory proteins to coordinate template translocation during processive telomeric DNA repeat synthesis. Telomerase is thus a fascinating polymerase, singular in function and unrivaled in complexity.

Control of Telomeric DNA Replication: Genetics, Molecular ..

AB - The cationic porphyrin 5,10,15,20-tetra-(N-methyl-4-pyridyl)porphyrin (TMPyP4) binds to quadruplex DNA and is thereby an inhibitor of human telomerase (Wheelhouse et al. J. Am. Chem. Soc. 1998, 120, 3261-3262). Herein the synthesis and telomerase-inhibiting activity of a wide range of analogues of TMPyP4 are reported, from which rules for a structure-activity relationship (SAR) have been discerned: (1) stacking interactions are critical for telomerase inhibition, (2) positively charged substituents are important but may be interchanged and combined with hydrogen-bonding groups, and (3) substitution is tolerated only on the meso positions of the porphyrin ring, and the bulk of the substituents should be matched to the width of the grooves in which they putatively lie. This SAR is consistent with a model presented for the complexation of TMPyP4 with human telomeric quadruplex DNA.

that is used as template for telomeric DNA synthesis.

N2 - The cationic porphyrin 5,10,15,20-tetra-(N-methyl-4-pyridyl)porphyrin (TMPyP4) binds to quadruplex DNA and is thereby an inhibitor of human telomerase (Wheelhouse et al. J. Am. Chem. Soc. 1998, 120, 3261-3262). Herein the synthesis and telomerase-inhibiting activity of a wide range of analogues of TMPyP4 are reported, from which rules for a structure-activity relationship (SAR) have been discerned: (1) stacking interactions are critical for telomerase inhibition, (2) positively charged substituents are important but may be interchanged and combined with hydrogen-bonding groups, and (3) substitution is tolerated only on the meso positions of the porphyrin ring, and the bulk of the substituents should be matched to the width of the grooves in which they putatively lie. This SAR is consistent with a model presented for the complexation of TMPyP4 with human telomeric quadruplex DNA.