Photochemistry ond Phorobralogy. Vol. 29. pp, X55 1 0 X5h. 0 Perg,,rnun Press Lld. 1979. Printcd in Great Brilmn
RESEARCH NOTE REVISED SPECTRA FOR THE INACTIVATION OF H A E M O P H I L U S I N F L U E N Z A E TRANSFORMING DNA BY MONOCHROMATIC ULTRAVIOLET LIGHT: EFFECT OF HISTIDINE M. J. PEAK*and R. W. TuvEsoNt Division of Biological and Medical Research, Argonne National Laboratory, Argonne, IL 60439. U.S.A. and tDepartment of Genetics and Developmcnt, University of Illinois, Urbana, I L 61801, U.S.A. (Receiwd 30 Ocroher 1978; uccupttd 31 Octohrr 197X) Abstract--It was reported previously that histidine sensitizes the genetic activity of Hurmophilus itlflucwrue transforming DNA to pure 334 nm ultraviolet light, Further measurements show that this apparent 334 nm sensitization was probably erroneous and that in fact, histidine protects DNA against inactivation by 334 nm light. This is now consistent with all previous observations that transforming DNA is protected by histidine against all near-UV wavelengths (above 320 nm) investigated. A modified spectrum for the protection of N. influenza transforming DNA by histidine against ultraviolet light is described.
MATERIALS AND METHODS
INTRODUCTION
All techniques and radiation eqiiipmcnt used werc exactly as dcscribed previously (Cabrera-Juire/ c’i
RESEARCH NOTE REVISED SPECTRA FOR THE INACTIVATION OF H A E M O P H I L U S I N F L U E N Z A E TRANSFORMING DNA BY MONOCHROMATIC ULTRAVIOLET LIGHT: EFFECT OF HISTIDINE M. J. PEAK*and R. W. TuvEsoNt Division of Biological and Medical Research, Argonne National Laboratory, Argonne, IL 60439. U.S.A. and tDepartment of Genetics and Developmcnt, University of Illinois, Urbana, I L 61801, U.S.A. (Receiwd 30 Ocroher 1978; uccupttd 31 Octohrr 197X) Abstract--It was reported previously that histidine sensitizes the genetic activity of Hurmophilus itlflucwrue transforming DNA to pure 334 nm ultraviolet light, Further measurements show that this apparent 334 nm sensitization was probably erroneous and that in fact, histidine protects DNA against inactivation by 334 nm light. This is now consistent with all previous observations that transforming DNA is protected by histidine against all near-UV wavelengths (above 320 nm) investigated. A modified spectrum for the protection of N. influenza transforming DNA by histidine against ultraviolet light is described.
MATERIALS AND METHODS
INTRODUCTION
All techniques and radiation eqiiipmcnt used werc exactly as dcscribed previously (Cabrera-Juire/ c’i
