Photochemistry of nucleic acids and their constituents

Journal Article · Sat Jan 01 04:00:00 EST 1972 · Photophysiology; (United States)

OSTI ID:5300171

Varghese, A J

These studies show that hydrates and cyclobutane dimers are formed in RNA and that both products can cause uv inactivation of RNA. Other pyrimidine photoproducts are also formed; their identities, as well as their possible roles in photoinactivation, are not known. At least in one instance there is a direct correlation between RNA-protein cross-links and uv inactivation. The presence of unusual bases in the RNA molecule might result in additional complexity in the photochemistry. For example, it has been shown that pseudouridine in sRNA yields 5-formyl-uracil (Tomasz and Chambers, 1966) and thiouridine in E. coli tRNA gives uridine (Pleiss and Cerutti, 1971) as photoproducts under certain irradiation conditions. According to Favre et al. (1971), irradiation of tRNA/sup Val/with monochromatic light (334 nm) produces specifically a cytosine-4-thiouracil adduct. The irradiated tRNA was fully acylated even though its affinity for the synthetase was decreased by a factor of three and no difference was observed between normal and irradiated RNA for ribosome binding in the presence of poly(U,G). The valine acylated to irradiated RNA was incorporated into polypeptide chains with a rate that was 2-fold slower than with normal RNA (Yaniv et al., 1971). There is evidence that a repair process similar to that of enzymatic photoreactivation of uv-damaged DNA exists also for RNA damage (Murphy and Gordon, 1971b).

• Research Organization: Univ. of Texas, Dallas
• OSTI ID: 5300171
• Journal Information: Photophysiology; (United States), Journal Name: Photophysiology; (United States) Vol. 7; ISSN PHCTB
• Country of Publication: United States
• Language: English

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