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On the interaction of actinomycin and DNA


Hyman, Richard Walter (1970) On the interaction of actinomycin and DNA. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/RJRA-PV20.


Experiments have been accomplished that (a) further define the nature of the strong, G-containing DNA binding sites for actinomycin D (AMD), and (b) quantitate the in vitro inhibition of E. coli RNA polymerase activity by T7 DNA-bound AMD.

Twenty-five to forty percent of the G's of crab dAT are disallowed as strong AMD binding sites. The G's are measured to be randomly distributed, and, therefore, this datum cannot be explained on the basis of steric interference alone. Poly dAC:TG binds as much AMD and as strongly as any natural DNA, so the hypothesis that the unique strong AMD binding sites are G and a neighboring purine is incorrect. The datum can be explained on the basis of both steric interference and the fact that TGA is a disallowed sequence for strong AMD binding.

Using carefully defined in vitro conditions, there is one RNA synthesized per T7 DNA by E. coli RNA polymerase. The rate of the RNA polymerase-catalyzed reaction conforms to the equation 1/rate = 1/kA(ATP) + 1/KG(GTP) + 1/KC(CTP) + 1/KU(UTP) T7 DNA-bound AMD has only modest effects on initiation and termination of the polymerase-catalyzed reaction, but a large inhibitory effect on propagation. In the presence of bound AMD, kG and kC are decreased, whereas kA and kU are unaffected. These facts are interpreted to mean that on the microscopic level, on the average, the rates of incorporation of ATP and UTP are the same in the absence or presence of bound AMD, but that the rates of incorporation of GTP and CTP are decreased in the presence of AMD.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemistry; actinomycin; DNA
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Davidson, Norman R.
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 December 1969
Funding AgencyGrant Number
Record Number:CaltechTHESIS:08122015-102840138
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9099
Deposited By: Dan Anguka
Deposited On:12 Aug 2015 18:20
Last Modified:09 Nov 2022 19:20

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