Monomerization of pyrimidine dimers in DNA by tryptophan-containing peptides: wavelength dependence

Journal Article · Mon Sep 01 04:00:00 EDT 1980 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575334· OSTI ID:6784952

Sutherland, J C; Griffin, K P

Tryptophan-containing peptides and proteins can sensitize the monomerization of pyrimidine dimers in ultraviolet-irradiated DNA; photoreactivating enzymes catalyze the light-induced monomerization of pyrimidine dimers in DNA. It has recently been proposed that a variety of tryptophan-containing proteins and peptides might be confused with true photoreactivating enzymes both in vivo and in vitro. We have thus characterized the wavelengths required for the tryptophan-sensitized dimer monomerization to determine if this process is distinguishable from true enzymatic photoreactivation. We find that 313-nm radiation can monomerize pyrimidine dimers in DNA in the presence of the peptide lysyl-tryptophyl-lysine; however, 334- 365-, and 405-nm radiation are ineffective for fluences up to 1 MJ/m/sup 2/. In contrast, each of these wavelengths is capable of monomerizing dimers in the presence of photoreactivating enzymes. Indeed, 334 and 365 nm are always more effective than 313-nm radiation in the case of true enzymatic photoreactivation. The inability of wavelengths other than those near 300 nm to drive the tryptophan-mediated reaction efficiently is consistent with recently reported spectroscopic experiments. The extreme differences in the wavelength specificities for true enzymatic photoreactivation and tryptophan-sensitized monomerization mean that it is easy to differentiate experimentally between the two phenomena. Consideration of the spectral distributions of conventional sources of photoreactivating light indicate that it is extremely unlikely that any of them could contain significant intensities of the wavelengths required for efficient tryptophan-sensitized monomerization of pyrimidine dimers. We thus conclude that tryptophan-sensitized monomerization cannot account for the disappearance of pyrimidine dimers from DNA in cells or cell extracts exposed to photoreactivating light.

• Research Organization: Brookhaven National Lab., Upton, NY
• OSTI ID: 6784952
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 83:3; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

550201 -- Biochemistry-- Tracer Techniques
560111* -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINO ACIDS
AZINES
AZOLES
BACTERIA
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CARBOXYLIC ACIDS
DATA
DIMERS
DNA
ELECTROMAGNETIC RADIATION
ENZYMES
ESCHERICHIA COLI
EXPERIMENTAL DATA
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INDOLES
INFORMATION
LABELLED COMPOUNDS
LYSINE
MICROORGANISMS
MONOMERS
NUCLEIC ACIDS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDES
PHOTOREACTIVATION
PROTEINS
PYRIMIDINES
PYRROLES
RADIATIONS
RECOVERY
REPAIR
TRITIUM COMPOUNDS
TRYPTOPHAN
ULTRAVIOLET RADIATION
WAVELENGTHS