Hachimoji DNA and RNA: A genetic system with eight building blocks

Reported here are DNA and RNA-like systems built from eight (hachi-) nucleotide letters (-moji) that form four orthogonal pairs. This synthetic genetic biopolymer meets the structural requirements needed to support Darwinism, including a polyelectrolyte backbone, predictable thermodynamic stability, and stereoregular building blocks that fit a Schrödinger aperiodic crystal. Measured thermodynamic parameters predict the stability of hachimoji duplexes, allowing hachimoji DNA to double the information density of natural terran DNA. Three crystal structures show that the synthetic building blocks do not perturb the aperiodic crystal seen in the DNA double helix. Hachimoji DNA was then transcribed to give hachimoji RNA in the form of a functioning fluorescent hachimoji aptamer. These results expand the scope of molecular structures that might support life, including life throughout the cosmos

Fabrication of Naphthalimide Chemosensor by Inkjet Printing on Paper for the Detection of Uric Acid in Solution

High uric acid (UA) concentrations are linked to many human health disorders. Currently, UA is detected in human samples through laboratory testing. However, laboratory testing is impractical in developing nations, which lack the diagnostic capability (trained professionals, complex laboratory equipment, and analytical instruments) necessary for this approach. The lack of resources leads to the spread of chronic illnesses in these countries. To combat this issue, a paper test strip is proposed that provides a measure of UA in a point-of-care setting without requiring the use of expensive instruments or qualified professionals. The rapid detection of UA in solution was achieved by a naphthalimide-based “turn-on” chemosensor. Divinyl sulfone was used to immobilize the chemosensor onto cellulose paper. A colorimetric detection technique was created that took advantage of photoinduced electron transfer (PET) technology, which allowed for the creation of a sensor whose fluorescence was directly proportional to the UA concentration. To interpret the results from the paper strips, a calibration curve was created that determined the concentration of UA in the solutions. The test strip was used to determine UA concentration in synthetic urine and grain samples. The results from the calibration curve show that UA concentration in the grain samples is within the range of the calibration curve, while it is slightly lower in the case of UA in synthetic urine due to possible quenching of the probe in urine

A mild and efficient method for the preparation of 5'-dimethoxytrityl-2'-deoxy-nucleoside using poly(4-vinylpyridine)-costyrene

370-371<span style="font-size:13.5pt;mso-bidi-font-size:6.5pt; font-family:HiddenHorzOCR;mso-hansi-font-family:" times="" new="" roman";mso-bidi-font-family:="" hiddenhorzocr;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" ar-sa"="">5'-O-4,4'-Dimethoxytrityl-2'-deoxynucleosides have been synthesized in high yield by the reaction of 2'-deoxynucleosides with 4, 4'-dimethoxytrityl chloride in acetonitrile using poly (4- vinylpyridine)-costyrene (styrene 10%).</span

Synthesis of sulfoxides by the oxidation of sulfides with polymer supported periodate ion

1184-118

Synthesis and Enzymology of 2′-Deoxy-7-deazaisoguanosine Triphosphate and Its Complement: A Second Generation Pair in an Artificially Expanded Genetic Information System

As with natural nucleic acids, pairing between artificial nucleotides can be influenced by tautomerism, with different placements of protons on the heterocyclic nucleobase changing patterns of hydrogen bonding that determine replication fidelity. For example, the major tautomer of isoguanine presents a hydrogen bonding <i>donor</i>–<i>donor</i>–<i>acceptor</i> pattern complementary to the <i>acceptor</i>–<i>acceptor</i>–<i>donor</i> pattern of 5-methylisocytosine. However, in its minor tautomer, isoguanine presents a hydrogen bond <i>donor</i>–<i>acceptor</i>–<i>donor</i> pattern complementary to thymine. Calculations, crystallography, and physical organic experiments suggest that this tautomeric ambiguity might be “fixed” by replacing the N-7 nitrogen of isoguanine by a CH unit. To test this hypothesis, we prepared the triphosphate of 2′-deoxy-7-deazaiso-guanosine and used it in PCR to estimate an effective tautomeric ratio “seen” by <i>Taq</i> DNA polymerase. With 7-deazaisoguanine, fidelity-per-round was ∼92%. The analogous PCR with isoguanine gave a lower fidelity-per-round of ∼86%. These results confirm the hypothesis with polymerases, and deepen our understanding of the role of minor groove hydrogen bonding and proton tautomerism in both natural and expanded genetic “alphabets”, major targets in synthetic biology

Synthesis and Enzymology of 2′-Deoxy-7-deazaisoguanosine Triphosphate and Its Complement: A Second Generation Pair in an Artificially Expanded Genetic Information System

As with natural nucleic acids, pairing between artificial nucleotides can be influenced by tautomerism, with different placements of protons on the heterocyclic nucleobase changing patterns of hydrogen bonding that determine replication fidelity. For example, the major tautomer of isoguanine presents a hydrogen bonding <i>donor</i>–<i>donor</i>–<i>acceptor</i> pattern complementary to the <i>acceptor</i>–<i>acceptor</i>–<i>donor</i> pattern of 5-methylisocytosine. However, in its minor tautomer, isoguanine presents a hydrogen bond <i>donor</i>–<i>acceptor</i>–<i>donor</i> pattern complementary to thymine. Calculations, crystallography, and physical organic experiments suggest that this tautomeric ambiguity might be “fixed” by replacing the N-7 nitrogen of isoguanine by a CH unit. To test this hypothesis, we prepared the triphosphate of 2′-deoxy-7-deazaiso-guanosine and used it in PCR to estimate an effective tautomeric ratio “seen” by <i>Taq</i> DNA polymerase. With 7-deazaisoguanine, fidelity-per-round was ∼92%. The analogous PCR with isoguanine gave a lower fidelity-per-round of ∼86%. These results confirm the hypothesis with polymerases, and deepen our understanding of the role of minor groove hydrogen bonding and proton tautomerism in both natural and expanded genetic “alphabets”, major targets in synthetic biology