Volume 1

Gene expression / Benjamin Lewin.

  • Lewin, Benjamin.
Date:
1974-1977
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Gene expression / Benjamin Lewin. Source: Wellcome Collection.

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    Sucrose gradient Free complete enzyme l 1 Complete enzyme - DNA Core^ enzyme - DIMA DNA bound core enzyme free complete free enzyme sigmo I I i Gel electrophoresis of RNA polymerase 8 o TD O L 1 ßß' ' - CT J\ a 1 ßß' i a |\ ßß' a RNA polymerase • J 1 1 b RNA polymerase + gh-1 DNA; 50mM KCl . ßß' 'a_ - a Wv. ç RNA polymerase + gh-1 DNA + NTPs ^ 50 mM KCl y bound same as ç but 200 mM KCl free 10 20 fractions Figure 6.5: sigma is released from RNA polymerase when transcription is initiated on phage gh-1 DNA. Left: sucrose gradients of RNA polymerase of P. putida. Right: analysis on acrylamide gels of the enzyme recovered from the main peak of the sucrose gradient. The gel system resolves the enzyme into three peaks, one containing both ß and ß\ one containing a, one corresponding to o. (a) free RNA polymerase contains all its poly peptide subunits, (b) polymerase bound to DNA in 50 mM KCl retains all subunits, (c) addition of nucleoside triphosphates forms an initiation