ライフサイエンスコーパス: nucleobase

1 h a reporter fluorophore on the same thymine nucleobase.

2 phere divalent metal ion coordination with a nucleobase.

3 e ionizing transition centered solely on the nucleobase.

4 trolled by the overall hydrophobicity of the nucleobase.

5 ble of differentiating between the G and 8OG nucleobase.

6 ime how SRA reads DNA and flips the modified nucleobase.

7 hanisms that all rely on protonating the 8OG nucleobase.

8 isomers with the desired orientation of the nucleobase.

9 ain of tyrosine 162 that replaces the lesion nucleobase.

10 mimetics in which the peptide backbone bears nucleobases.

11 dispersed binding site with approximately 20 nucleobases.

12 us oxidized, alkylated, or otherwise damaged nucleobases.

13 e through low-lying electronic states of the nucleobases.

14 nsic photostability of canonical DNA and RNA nucleobases.

15 onated peptides and base-pairing energies of nucleobases.

16 electivity for both canonical and epigenetic nucleobases.

17 rohydride reduction, single 5-formylcytosine nucleobases.

18 for their binding to all five human cytosine nucleobases.

19 integrity by locating and excising aberrant nucleobases.

20 l cyanide species (CN.) for the synthesis of nucleobases.

21 lubility of guanine as compared to the other nucleobases.

22 but also an adduct that coordinates multiple nucleobases.

23 ir pathway by locating and excising aberrant nucleobases.

24 en or exocyclic nitrogen and oxygen atoms of nucleobases.

25 MepR makes no hydrogen bonds to major groove nucleobases.

26 LNA: i.e., through functionalization of LNA nucleobases.

27 ace the intermediates back to their original nucleobases.

28 these compounds: canonical and non-canonical nucleobases.

29 se pairing, respectively, over the canonical nucleobases.

30 tion for oxidation was 720 8-oxodG per 10(6) nucleobases.

31 cyclic carbohydrate phosphates with the free nucleobases.

32 It preferred nucleosides compared with nucleobases.

33 The introduction of cytosine nucleobase 2 into position 24 of RRM1 increased the affi

34 The fluorescent nucleobase 2-aminopurine replaced three individual adeni

35 odel prebiotic reaction between a pyrimidine nucleobase (2,4,6-triaminopyrimidine, TAP) and ribose, w

36 ining the standard nucleobases and two added nucleobases (2-amino-8H-imidazo[1,2-a][1,3,5]triazin-4-o

37 In comparison, the introduction of uracil nucleobase 3 had a minimal effect on DNA affinity.

38 ith a novel linker able to stack to adjacent nucleobases, a new strategy previously not applied for a

39 ose nucleoside phosphonates with the natural nucleobases adenine, thymine, cytosine, and guanosine ha

40 In addition, the GNA-T nucleobase adopts a rotated conformation in which the 5-

41 lly, we observed matching between amino acid-nucleobase affinities and corresponding mRNA sequences i

42 significant matching between an amino acid's nucleobase affinity and corresponding codon content in b

43 ead of directly interacting with the damaged nucleobase, AlkD recognizes aberrant base pairs through

44 Site-specific substitution with (15)N-nucleobases allowed observation of stable hydrogen bond

45 ogen bearing acyclic molecules and prebiotic nucleobases along with vitamins found in meteorites.

46 1-DNA interaction, as well as the ability of nucleobase amino acid 1 to stabilize RRM1-DNA interactio

47 The results support the idea of using nucleobase amino acids as protein constituents for contr

48 ive transcription factor hnRNP LL containing nucleobase amino acids at specific positions have been p

49 Four nucleobase amino acids were introduced into RRM1 at one

50 lem in chemical selectivity, inasmuch as the nucleobase (an undesired site of reaction) is usually mo

51 -(p-nitrophenyl)pyrrolocytosine (p-NO2-PhpC) nucleobase analogs.

52 Two structurally simplified nucleobase analogues (1 and 4) lacking both the N-1 and

53 ium-sulfate gradient encapsulation method to nucleobase analogues, a liposomal entrapment method once

54 wo chiral ferrocene derivatives containing a nucleobase and a hydroxyalkyl group.

55 totype contains a cyclopentyl linker between nucleobase and alpha-carboxyphosphonate and preferential

56 nd electronic structure on the nature of the nucleobase and are in good agreement with theoretical ca

57 pi-stacking interactions between the lesion nucleobase and aromatic side chains in the glycosylase a

58 e properties and chemical reactivity of each nucleobase and attempt to provide some general principle

59 elf-cleavage reaction using a combination of nucleobase and metal ion catalysis.

60 is method is irrespective of the 5'-terminal nucleobase and most interestingly can be directly extend

61 tively, is based on hydrogen bonding between nucleobase and phosphodiester moieties.

62 n a non-natural N(4) -amino-2'-deoxycytidine nucleobase and the aldehyde residue of an abasic site in

63 fragmented at the N-glycosidic bond provide nucleobase and/or ribose or 2'-deoxyribose fragment ions

64 een shown to be able to differentiate single nucleobases and amino acids in short sequences.

65 st time, stacking free energies between five nucleobases and anthracene were determined experimentall

66 acts as guanine when interacting with other nucleobases and base pairs most favorably with cytosine.

67 ef history of the development of fluorescent nucleobases and explore their utility as tools for addre

68 It reacts with exocyclic amino groups of DNA nucleobases and forms adducts/lesions leading to carcino

69 and AlkD are specific for cationic alkylated nucleobases and have a distinctive HEAT-like repeat (HLR

70 activation pathways bestow photostability on nucleobases and hence preserve the structural integrity

71 N-Hydroxylated nucleobases and nucleosides as N-hydroxylaminopurine (HA

72 oside analogs to the corresponding canonical nucleobases and nucleosides upon reconstitution with the

73 ul technique for characterizing noncanonical nucleobases and other chemical modifications in small RN

74 active intermediate that pyridyloxobutylates nucleobases and phosphate backbone of DNA.

75 ights into the interactions between HgII and nucleobases and the structural basis for the rational de

76 ter genetic alphabet containing the standard nucleobases and two added nucleobases (2-amino-8H-imidaz

77 t stationary phases, the separations of both nucleobases and weak acids/weak bases on these gradient

78 sition (comparable numbers of A, U, G, and C nucleobases) and of varying length and sequence, and ani

79 mized with a combination of sugar, backbone, nucleobase, and 3'- and 5'-terminal modifications.

80 e subtle balance between different backbone, nucleobase, and ribose conformations, finely regulated b

81 rophosphorescent transition metal complexes, nucleobases, and amino acids.

82 r substrates for further installation of the nucleobases, and even simple nucleophiles, such as azido

83 cancer with various amino acids, inositols, nucleobases, and glutathione also altered.

84 molecules, coordination complexes, peptides, nucleobases, and saccharides.

85 d a combination of different leaving groups, nucleobases, and templating sequences to uncover the fac

86 lterations in base pairing properties of the nucleobases, and the mechanisms of ribosomal decoding co

87 d peptides containing push-pull side chains, nucleobases, and their nucleosides and nucleotides, is a

88 Capture of nucleobase- and phosphate-deprotected DNA sequences rele

89 Rare tautomeric and anionic nucleobases are believed to have fundamental biological

90 interactions between aromatic compounds and nucleobases are crucial in recognition of nucleotides an

91 Purine nucleobases are excellent ligands for metal ions, formin

92 tion of formamide up to concentrations where nucleobases are formed.

93 ase-peptide conjugates (NPCs), where achiral nucleobases are helically displayed on the surface of fi

94 lds, whereas the triplet yields of canonical nucleobases are nearly zero.

95 ble via reactions explored previously, while nucleobases are presumed to have been available from hyd

96 Cytosine nucleobases are shown to alter the adhesion of the DNA t

97 We show that RNA nucleobases are synthesized in these experiments, strong

98 d formation between ribose and the canonical nucleobases, as well as the inability of nucleosides to

99 ssed in terms of the ability of the modified nucleobases, as well as their natural counterparts, to s

100 se results suggest that the SLC4, SLC26, and nucleobase-ascorbate transporter families all share an e

101 s with UapA, a xanthine transporter from the nucleobase-ascorbate transporter family, show that the d

102 UraA H+-uracil symporter is a member of the nucleobase/ascorbate transporter (NAT) family of protein

103 We show that the nucleobase at -1 is not essential but its presence and i

104 trochemically between all four canonical DNA nucleobases at a single site within a target sequence of

105 rrangements of aromatic amino acids with the nucleobases at the junction core.

106 ist, the relative ease of oxidizing the four nucleobases being one such example.

107 However, the data show a pronounced nucleobase bias with a preference for binding poly (U) o

108 anding of the interactions between Ag(I) and nucleobases, but also provide a unique structural compon

109 epair enzymes that remove alkyl adducts from nucleobases by oxidative dealkylation.

110 ite-specific installation of light-removable nucleobase-caging groups as well as photocleavable backb

111 itation, we have site-specifically installed nucleobase-caging groups within a plasmid promoter regio

112 mic considerations strongly suggest that all nucleobases can undergo ultrafast charge separation when

113 ed secondary active transport protein of the nucleobase-cation-symport family and a member of the wid

114 t of DNA, off-resonant excitonic coupling to nucleobases, charge-transfer, and resonant excitonic cou

115 arises from base pairing of the four-letter nucleobase code to form a double helix.

116 The nucleobases comprising DNA and RNA aptamers provide cons

117 s and the pathway, revealing the dynamics of nucleobase conformational exchange during the folding tr

118 design to optimize the sequence identity and nucleobase conformations of an RNA to match a desired ba

119 AMP; and (ii) aprataxin makes more extensive nucleobase contacts with guanine than with adenine, via

120 polarity that may be established by protein-nucleobase contacts.

121 These metabolites included amino acids, nucleobase-containing compounds and lysophospholipids.

122 hemistry reactions were now combined to form nucleobase-containing sequence-controlled polymers in si

123 G-C dinucleoside can be inhibited using the nucleobase cytosine.

124 ndom, potentially leading to accumulation of nucleobase damage and mutations at specific sites within

125 HOMO-LUMO gaps than the terthiophene-linked nucleobases (DeltaE(g) approximately 1.8 eV vs 2.4 eV ba

126 monstrate the site-specific incorporation of nucleobase derivatives bearing fluorophores or affinity

127 g way to engineer complex, optically diverse nucleobase-derived nanomaterials.

128 y, these studies highlight the importance of nucleobase desolvation as a key physical feature that en

129 is controlled by energetics associated with nucleobase desolvation, whereas the rate constant for th

130 ion: a Ag10(+6) cluster develops within a 20-nucleobase DNA binding site, and this complex segregates

131 Observation of the nucleobases during folding provides a new perspective on

132 l reactions to form homopolymers of a single nucleobase (e.g., poly(A)n ) or homopolymers of specific

133 ions of amino acids that contact the guanine nucleobase efface kinase activity in vitro and Trl1 func

134 to the unique base-pairing properties of the nucleobases elicited by the inversion of the configurati

135 A truly universal nucleobase enables a host of novel applications such as

136 of peptide nucleic acid (PNA) with unnatural nucleobases enables the formation of PNA-RNA triplexes.

137 rmed between nucleotides bearing hydrophobic nucleobases, exemplified by the pair formed between d5SI

138 ing the fluorophore and quencher on the same nucleobase facilitates the design of short probes contai

139 insidious because neither of its constituent nucleobases faithfully transmit genetic information from

140 se, and reduced cost indicate the promise of nucleobases for future OLED development.

141 2-Thio-uridine (s(2)U) is a modified nucleobase found in certain tRNAs.

142 2-thiouridine (s(2)U) is a modified nucleobase found in tRNAs and known to stabilize U:A bas

143 alyzes hydrolytic cleavage of the aberrant A nucleobase from the DNA backbone.

144 We simulated the high-energy synthesis of nucleobases from formamide during the impact of an extra

145 ence: Structural modifications of individual nucleobases (G > A > C) --> DNA backbone modifications -

146 s the context similarity of two stretches of nucleobases given the similarity over distributions of t

147 ginine, the energy carrier creatine, and the nucleobase guanine.

148 s of these compounds incorporating different nucleobases has been efficiently completed starting from

149 Reactions that target nucleobases have been crucial in the development of new

150 Overall, the results show how nucleobase heterocycles can be installed within pi-syste

151 In both structures, Z:P pairs fit canonical nucleobase hydrogen-bonding parameters and known DNA hel

152 termediate in purine catabolism, the inosine nucleobase hypoxanthine is also one of the most abundant

153 es are well employed as a strategy to modify nucleobase in nucleoside analogues, although rare exampl

154 agents, can induce the carboxymethylation of nucleobases in DNA.

155 metal binding reactions involving unmodified nucleobases in duplex DNA.

156 positions and local content of modified DNA nucleobases in genomic DNA.

157 ful strategy to probe functions of conserved nucleobases in large RNAs.

158 tion of translation by methylation of purine nucleobases in mRNA.

159 ive damage to DNA and hole transport between nucleobases in oxidized DNA are important processes in l

160 ubstitutions to probe functions of conserved nucleobases in ribonuclease P (RNase P).

161 ne is also one of the most abundant modified nucleobases in RNA and plays key roles in the regulation

162 rface pocket that specifically binds adenine nucleobases in the 1 position (t1) of target RNAs.

163 o explore the interaction of nucleosides and nucleobases in the context of the Maillard reaction and

164 with an overview of the photophysics of the nucleobases in the gas phase and in solution.

165 The dye prefers to bind nucleobases in the order (kcal/mol): G (1.3) > T (0.9) >

166 hensive numerical model for the evolution of nucleobases in warm little ponds leading to the emergenc

167 The molecular recognition properties of the nucleobases instruct the formation of complex three-dime

168 ibe the inference of pairwise amino acid-RNA nucleobase interaction preferences using structural data

169 ular self-assembly because of their specific nucleobase interactions and defined length scale.

170 The role of amino acid-RNA nucleobase interactions in the evolution of RNA translat

171 sting a potential role for direct amino acid-nucleobase interactions in the genesis of amino acid-bas

172 bring the transiently populated hole carrier nucleobases into better aligned geometries on the nanose

173 a uracil-azobenzene derivative in which the nucleobase is conjugated to a phenyldiazene tail is stud

174 Interference by the nucleobase is minimized by the use of indium(III) trifla

175 d disadvantages of both types of fluorescent nucleobases is made, along with a perspective into the f

176 Instead of contacting the nucleobase itself, the AlkD active site interacts with t

177 sions may reduce the electron density at the nucleobases, making them prone to further modifications

178 This presentation of nucleobases may find applications in providing molecular

179 sults provide insights into the effects that nucleobase modification has on RNA structure and thermod

180 Neither nucleobase modification nor nucleotidyl transfer has pre

181 The realization that nucleobase modifications can greatly enhance the propert

182 Nucleobase modifications dramatically alter nucleic acid

183 A growing number of nucleobase modifications in messenger RNA have been reve

184 on histone proteins in the nucleosome and by nucleobase modifications on chromosomal DNA.

185 However, nucleobase modifications such as alkylation to the N2 po

186 also serve as a direct detection method for nucleobase modifications.

187 reveal a widened active site cavity near the nucleobase moiety compared to the human enzyme.

188 elevated temperatures lead to the release of nucleobases most likely via the traditional oxocarbenium

189 In this work, nucleobases (NBs), constituents of DNA and RNA polymers,

190 The building blocks of nucleic acids (i.e. nucleobases, nucleosides, and nucleotides) are desirable

191 ical systems (amino acids, peptides, sugars, nucleobases, nucleosides, and nucleotides).

192 oxygen atoms of the corresponding pyrimidine nucleobase (O2), and the 2'-SCF3 moieties participated i

193 ose direct coordination of metal ions by the nucleobases of conserved uridine and guanosine in helix

194 Thus, modified duplexes with an array of nucleobases on the exterior of the duplex were designed.

195 The addition of silylated nucleobases onto model C2-fluorinated dithioacetal subst

196 nduces higher lipophilicity than fluorine on nucleobase or in the backbone.

197 nated 2'-deoxyribonucleosides with canonical nucleobases or 2'-deoxy-2'-fluoroisocytidine ((F)iCd, 1c

198 ure conversion of brominated and chlorinated nucleobases or nucleobase precursors as starting materia

199 and stability of oligonucleotides containing nucleobase- or 4'-hydroxymethyl-transposed nucleotides a

200 The use of oligonucleotides containing nucleobase- or 4'-hydroxymethyl-transposed nucleotides a

201 which uncouples 2-oxoglutarate turnover from nucleobase oxidation.

202 A molecule that contains an orthogonal added nucleobase pair.

203 e ester (Cyt-S4), revealed Watson-Crick type nucleobase pairing of 6TG.

204 ved for a 'control' oligonucleotide in which nucleobase pairs are replaced by .

205 nucleobase pairs follow standard rules for Watson-Crick

206 ne how the presence of multiple, consecutive nucleobase pairs might impact helical structure.

207 mino-imidazo[1,2-a]-1,3,5-triazin-4(8H)-one) nucleobase pairs on the structural parameters of duplex

208 Ionized nucleobases participate in pairing interactions outside

209 ogenic proteins, we show that a conjugate of nucleobase, peptide, and saccharide binds to peptides fr

210 ical fibrils through chiral self-assembly of nucleobase-peptide conjugates (NPCs), where achiral nucl

211 oduction and biosynthesis of phospho-sugars, nucleobases, peptidoglycan and some amino acids.

212 Nucleoside fragments composed of the nucleobase plus some carbons of the ribose ring were als

213 The inter-RRM linker forms the lid of the nucleobase pocket and we show using structure-guided mut

214 lly with the AG dinucleotide sequence via a "nucleobase pocket" formed by the beta-sheet surface of R

215 t processes on the prebiotic Earth, if other nucleobases preceded those of extant life.

216 of brominated and chlorinated nucleobases or nucleobase precursors as starting materials.

217 gh-throughput NMR method for the analysis of nucleobase preference in protein-RNA interactions.

218 Furthermore, we showed that knowledge of nucleobase preferences allows statistically significant

219 reprogramming the self-assembly of existing nucleobases presents an alternative route to expand the

220 her levels than the corresponding methylated nucleobase products (m(5)C and m(6)A) in total RNA isola

221 rines at -1, an exocyclic amine at C2 on the nucleobase promotes cleavage at an alternative site and

222 is indifferent to the identity of the 3'-OH nucleobase, provided that it is correctly paired.

223 Neither nucleobase radical produces direct strand breaks or alka

224 Nucleobase radicals are a major family of reactive speci

225 Nucleobase radicals are the major intermediates generate

226 considered in conjunction with reports that nucleobase radicals produce 1, this chemistry explains w

227 obic conditions where 1 can be produced from nucleobase radicals.

228 These provide insights into their nucleobase recognition mechanisms and reveal the ability

229 sidue prevent stable insertion of C into the nucleobase recognition pocket within the enzyme active s

230 Taking advantage of metal-nucleobase recognition, we highlight the possibility of

231 Here, we have studied the effect of select nucleobase, ribose and backbone modifications on phospho

232 ng of the nitro group on Z with the adjacent nucleobase ring in the A-form duplex.

233 equences with targeted molecules to rank the nucleobase sensing performance.

234 a heteroduplex of DNA/aeg-PNA with identical nucleobase sequence were measured.

235 and phosphate backbone contacts, rather than nucleobase sequence, usually determines substrate specif

236 issociation of the duplex is dictated by the nucleobase sequence.

237 (A)n ) or homopolymers of specific repeating nucleobase sequences (e.g., poly(ATC)n).

238 ibozyme that performs both reactions, with a nucleobase serving as initial acceptor moiety.

239 d oligonucleotides with 2,6-diaminopurine as nucleobase showed no significant thermal stability chang

240 bonds by utilizing the N donor atoms of the nucleobase skeleton.

241 3' CDN that anemone STING recognizes through nucleobase-specific contacts not observed in human STING

242 A polymerases differs from the nature of the nucleobase-specific kinetic interaction of the cyclopent

243 and donor along with a modified guanine (G) nucleobase, specifically 8-(4'-phenylethynyl)deoxyguanos

244 set of quasi-degenerate RNAs and define the nucleobase specificity.

245 ctly to the backbone and one directly to the nucleobase stack.

246 stabilized by long-range hydrogen bonds and nucleobase stacking and by a triloop that forms within i

247 Urea-nucleobase stacking interactions have been shown to be c

248 0% smaller hydrodynamic radius and disrupted nucleobase stacking.

249 nucleoside tetraphosphate agonists with both nucleobases substituted.

250 ngle, strategically positioned 2-aminopurine nucleobase substitution.

251 inducing a total of approximately 26% single-nucleobase substitutions at the lesion site, whereas rep

252 eals that Msd specifically acts on mutagenic nucleobases such as 5-azacytosine and isoguanine and doe

253 rity of the X-bonds is formed by halogenated nucleobases, such as bromouridine, and feature excellent

254 present a summary of the most commonly used nucleobase, sugar and backbone modification, and conjuga

255 obtained were amino acids, carboxylic acids, nucleobases, sugars, and, most notably, four nucleosides

256 Importantly, the nucleobase surrogates marginally affected the structure

257 showing the outstanding sensitivity of both nucleobase surrogates to the small structural changes ac

258 m, we have utilized two distinct fluorescent nucleobase surrogates, 2-thienyl-3-hydroxychromone nucle

259 These findings demonstrate that a nucleobase tetramer arranged as two stacked base pairs a

260 ic stability by excising chemically modified nucleobases that alter normal DNA metabolism.

261 We focus on modified nucleobases that are substrates for enzymes that excise

262 Synthetic fluorescent nucleobases that can be incorporated into nucleic acids

263 nt intermediate states by observing selected nucleobases that contribute specific interactions to the

264 conformational rearrangements of individual nucleobases that occur during ligand recognition of the

265 etal ions and the RNA moieties, particularly nucleobases, that bind metal ions is important in RNA ca

266 ry dust particles delivered organics such as nucleobases (the characteristic molecules of nucleotides

267 otophysical mechanisms in sulfur-substituted nucleobases (thiobases) is essential for designing prosp

268 alysis through the N3 position of an adenine nucleobase, thus expanding the repertoire of known mecha

269 We demonstrate the concept using the nucleobase thymine at the oxygen K-edge, and unambiguous

270 For the nucleobase thymine, the oxygen Auger spectrum shifts tow

271 sharp kink in the DNA, exposing the damaged nucleobase to active site residues that project into the

272 t transfer of the donor glycosyl moiety from nucleobase to hydroxyl.

273 ability is due to propensity of the guanine nucleobase to self-associate into stable higher-order as

274 up to a linker moiety and an attachment of a nucleobase to the other end of the linker by a Mitsunobu

275 Rearranging hydrogen bonding groups adds nucleobases to an artificially expanded genetic informat

276 th known crystal structure to conjugate with nucleobases to form nucleopeptides.

277 iazoacetate intermediate that can react with nucleobases to give carboxymethylated DNA adducts such a

278 Moreover, the rapid losses of nucleobases to pond seepage during wet periods, and to U

279 he aromatic residues form a platform for RNA nucleobases to stack.

280 nges to raise the apparent pKa of protonated nucleobases to values above physiological pH.

281 This review focuses on 4'-hydroxymethyl- or nucleobase-transposed nucleosides, nucleotides, and nucl

282 activities of all known 4'-hydroxymethyl- or nucleobase-transposed nucleosides, nucleotides, and nucl

283 phosphate-containing nucleotides, varying in nucleobase type (A, G, C, U, m(7)G), phosphate chain len

284 TDG exhibits no significant binding to free nucleobases (U, T, hmU), indicating a Kd >> 10 mM.

285 Krebs cycle, the pentose phosphate pathway, nucleobases, UDP-sugars, glycogen, lipids, and proteins

286 in the acetyl side chain (-CHF-CO-) bearing nucleobase uracil (5-F/5-CF3-U).

287 The RNA nucleobase uracil can suffer from photodamage when expos

288 irect incorporation of functional artificial nucleobases using a simple hairpin recognition element.

289 tegy involved the sequential introduction of nucleobases, using two stereocontrolled N-glycosidation

290 an alkyl chain and ethynyl attachment to the nucleobase was designed and incorporated into DNA by pri

291 nzymes and chemically synthesized ribose and nucleobase, we have developed an inexpensive, rapid chem

292 stablished that the 1'-CN group and C-linked nucleobase were critical for optimal anti-EBOV potency a

293 Their constituent nucleobases were primarily meteoritic in origin and not

294 Arylated nucleobases were synthesized by visible light photocatal

295 by administration of glutamate, alphaKG, or nucleobases with N-acetylcysteine.

296 se events taking place after reaction of DNA nucleobases with OH radical have been widely investigate

297 sulting from O2 trapping, add to 5'-adjacent nucleobases, with a preference for dG.

298 the pol delta holoenzyme ensures that every nucleobase within an Okazaki fragment is faithfully dupl

299 far for pi-conjugated molecules that include nucleobases within the pi-framework.

300 ing this to be the case with two nonstandard nucleobases (Z, 6-amino-5-nitro-2(1H)-pyridone and P, 2-