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Site‐Specific Insertion of the (5 R *) and (5 S *) Diastereoisomers of 1‐[2‐Deoxy‐β‐ D ‐ erythro ‐pentofuranosyl]‐5‐hydroxyhydantoin into Oligodeoxyribonucleotides
Author(s) -
Muller Evelyne,
Gasparutto Didier,
Lebrun Colette,
Cadet Jean
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200106)2001:11<2091::aid-ejoc2091>3.0.co;2-2
Subject(s) - chemistry , diastereomer , phosphoramidite , synthon , phosphodiester bond , oligonucleotide , stereochemistry , biochemistry , dna , rna , gene
The insertion of the (5 R *) and (5 S *) diastereoisomers of 1‐[2‐deoxy‐β‐ D ‐ erythro ‐pentofuranosyl]‐5‐hydroxyhydantoin ( 1 ) − a major oxidation product of 2′‐deoxycytidine upon exposure to · OH radicals, excited photosensitizers, or ozone − into oligonucleotides is reported. It was achieved by means of phosphoramidite chemistry, using the solid‐phase synthesis approach. The synthesis of the phosphoramidite synthon 7 required 6 steps from 3′‐ O ‐( tert ‐butyldimethylsilyl)‐2′‐deoxycytidine and involved protection of the secondary hydroxy group (5‐OH) of the modified base by the nonstandard levulinyl group. The modified phosphoramidite synthon 7 was efficiently incorporated into several oligonucleotides (3‐ mer , 14‐ mer , 22‐ mer ) by solid‐support assembling. The presence and the integrity of the (5 R *) and (5 S *) diastereoisomers of 1‐[2‐deoxy‐β‐ D ‐ erythro ‐pentofuranosyl]‐5‐hydroxyhydantoin in the synthetic oligomers was confirmed by electrospray ionization mass spectrometry, together with HPLC and MALDI‐TOF mass‐spectrometric analyses of enzymatic digestions. The use of exonucleases (calf spleen phosphodiesterase and bovine intestinal mucosa phosphodiesterase) clearly showed that enzymatic hydrolysis of the phosphodiester bonds between the (5 R *) and (5 S *) diastereoisomers of 1‐[2‐deoxy‐β‐ D ‐ erythro ‐pentofuranosyl]‐5‐hydroxyhydantoin and normal 2′‐deoxyribonucleosides is prevented, while endonuclease (nuclease P 1 ) is able to cleave the lesion residue from the oligonucleotides.