DNA as energy store

DNA as energy store

1. DNA as an energy store An often overlooked function of DNA in a bacterial nucleus or nucleoid is that it

   • as a reserve of energy to facilitate the transit of DNA
   • as a reserve of energy to facilitate the transit RNA polymerases
   • Topoisomerases
     • can establish and maintain a supercoiling equilibrium state, DNA replication and transcription processes generate transient changes in DNA supercoiling after translocation of protein complexes throughout DNA
       • so
         • DNA as an energy store An often overlooked function of DNA in a bacterial nucleus or nucleoid is that it can act as a reserve of energy to facilitate the transit of DNA and RNA polymerases
           • However,
             • recent estimates suggest that such a strategy to stabilize the double helix would allow the DNA of an extremophile
               • "Thermus thermophilus"
                 • to maintain sufficient stability for biological function up to a temperature of 106 ° C or 15 ° C higher than that of Maximum value for the free DNA observed in the absence of topological restrictions
                   • But the storage of negative supercoils also has the Supercoil negative Relaxed Supercoil positive
                     • If the DNA is already packaged as a negative supercoil, the release of these negative supercoils could effectively neutralize some or all of the positive superhelicity generated by an advancing enzyme and thus, at least partially counteract any inhibitory effect of Positive twist in the procession of the fused bubble within the polymerase complex
                       • but
                         • However, they can, and do, by binding proteins retain negative superhelicity generated by DNA translocations.
                           • Although both the octamer of histones and the HMGB proteins limit negative superhelicity, the octamer binds to twisted DNA and HMGB proteins do not cross-link with DNA. Because distortion is favored by higher superhelical densities, it can be speculated that HMG domains stabilize the high nascent negative superhelicity generated by DNA translocations and only later is part of this histone octamer-restricted superhistory
                             • Magnitude have the potential to alter the superhelicity partition between torsion and contortion. Induction of superhelicity in a DNA domain restricted by a fixed elongated DNA translocase moving in the direction of the arrow. Negative superhelicity is generated upstream of the translocant enzyme and positive superhelicity downstream.
                               • so in cloncution:
                                 • H indicates a superhelical density. If the packaged DNA constituted a reservoir of energy to modulate gene expression, the nature of the packaging could depend on the availability of energy. During the late stationary phase of growth when the cells are deprived of energy, the nucleotide body collapses and the DNA is packaged by the highly abundant protein.