RNA polymerase subunits

Payne, J.M. Dahmus, M.E. Partial purification and characterization of two distinct protein kinases that differentially phosphorylate the carboxyl-terminal domain of RNA polymerase subunit Ila. J. Biol. Chem., 268, 80-87 (1993)... 

RNA-polymerase]-subunit kinase (Protein kinases are in a state of review by the NC-IUBMB. This EC class will presumably be... 

Each of the three eukaryotic RNA polymerases contains 12 or more subunits and so these are large complex enzymes. The genes encoding some of the subunits of each eukaryotic enzyme show DNA sequence similarities to genes encoding subunits of the core enzyme (a2PP ) of E. coli RNA polymerase (see Topic G2). However, four to seven other subunits of each eukaryotic RNA polymerase are unique in that they show no similarity either with bacterial RNA polymerase subunits or with the subunits of other eukaryotic RNA polymerases. 

The method described here allows for very predse exdsion of protein bands from the Immobilon matrix. As an example, the elution off. coli RNA polymerase subunits is shown in Fig. 1. Such predse exdsicm of protein bands is much more dillicult when they are cut out of polyacrylamide gels. 

Components of the archaeal translation apparatus, however, display an intra-domain diversity, not encountered within the other two domains. This situation is exemplified by (i) the lack of a uniform compatibility between ribosomes and elongation factors from different archaeal lineages (see section 5.2) (ii) the impressive diversity of archaeal ribosomes and factors in their response to a host of protein synthesis inhibitors (see section 4) (iii) the heterogeneity in shape, mass and composition of archaeal ribosomal subunits (see sections 2.6.2, 2.6.3). Importantly, within-domain diversity is also exemplified by the different complexities of the RNA polymerase subunit patterns from the sulfur-dependent and the methanogenic-halophilic archaea (see Zillig et ah. Chapter 12 of this volume). 

Each of these sorts of data also supports the deep split within the archaea, into what Woese, Kandler and Wheelis [10] call Euryarchaeota and Crenarchaeota. What the various data sets do not tell us unequivocally is whether, as a monophyletic assemblage, archaea are more recently diverged from eucarya or instead branch with the bacteria. As chapters in this volume reveal, ribosomal protein genes, those for RNA-polymerase subunits and translation elongation factors and some enzymes of metabolism (HMG-CoA reductase, for example [11]) show strong similarity specifically to their eukaryotic homologs, but others exhibit eubacterial affinities, or seem unique. 

C/N] RPB5, RNA polymerase subunit from Methanobacterium thermoautotrophicum 77 41 217... 

Minakhin, L., Bhagat, S., Brunning, A., Campbell, E.A., Darst, S.A., Ebright, R.H., and Severinov, K. (2001) Bacterial RNA polymerase subunit omega and eukaryotic RNA polymerase subunit RPB6 are sequence, structural, and functional homologs and promote RNA polymerase assembly. Proc. Natl. Acad. Sci. USA, 98, 892-897. 

In addition to their core subunits related to the E. coli RNA polymerase subunits, all three yeast RNA polymerases contain four additional small subunits, common to them but not to the bacterial RNA polymerase. Finally, each eukaryotic polymerase has several enzyme-specific subunits that are not present In the other two polymerases. Gene-knockout experiments In yeast Indicate that most of these subunits are essential for cell viability. Disruption of the few polymerase subunit genes that are not absolutely essential for viability nevertheless results in very poorly growing cells. Thus It... 

---