Biochemistry 2280A Lecture Notes - Lecture 2: Catabolite Repression, Chromatin, Nucleosome
5 Mar 2014
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The enzyme that makes rna transcripts using dna as a template and nucleoside triphosphates (ntps) as substrates. The key molecules that make rnas from dna! It is a multi-subunit enzyme; 4 subunits: two alpha subunits, a beta subunit, and a beta prime subunit. The core enzyme does not recognize promoters; rather the promoter specificity of rna polymerase is determined by the sigma subunit. Enzyme + sigma subunit = rna polymerase holoenzyme. The sigma subunit recognizes and contacts the -10 and -35 sequences; makes base. Sigma subunits are one of the many examples demonstrating the importance of protein- contact required for recognition nucleic acid interactions. One reason is that some genes have better (more attractive) -10 and -35 sequences. The closer the sequences are closer to the consensus sequences, the better and. This is not a dynamic regulation as the genes cannot change their -10 and -35 higher levels of expression sequences; it is fixed.
