Biomaterial Database

Structural studies on yeast RNA polymerases. Existence of common subunits in RNA polymerases A(I) and B(II). 1976

J M Buhler, and F Iborra, and A Sentenac, and P Fromageot

The subunits of yeast RNA polymerases A(I) and B(II) were characterized using several techniques. The present studies demonstrate that the A and B enzymes possess three subunits, which are indistinguishable on the basis of molecular weight, isoelectric point, and fingerprint pattern. The three common subunits belong to the small molecular weight components of the enzymes. By polyacrylamide gel electrophoresis with sodium dodecyl sulfate they migrate with apparent molecular weights of 27,000, 23,000, and 14,500, respectively. A two-dimensional subunit mapping technique on polyacrylamide gel was used to separate the subunits according to isoelectric point and molecular weight. The common polypeptides co-migrated on three spots corresponding to isoelectric points of 9.2 (27,000), 4.5 (23,000), and 4.6 (14,500). The fingerprints of the 35S-labeled tryptic peptides of the presumptive common subunits were found to be essentially identical. Finally, the presence of common subunits was supported by the fact that antibodies against pure RNA polymerase A cross-react with and inhibit RNA polymerase B. Except for the common subunits, it is likely that RNA polymerases A and B are primarily made of distinct gene products for the following reasons. A total of 13 polypeptide chains are present in enzyme A, whereas 10 polypeptides are found in enzyme B. The molecular weight, isoelectric point, and sulfur content of the majority of these polypeptide chains are different in the two enzymes. No similarity was found in the 35S-peptide fingerprint from a number of A and B subunits of slightly different molecular weight. Finally, antibodies against the largest subunit from RNA polymerase A do not cross-react with or inhibit RNA polymerase B. The data are discussed in terms of structural organization of eukaryotic RNA polymerases.

UI	MeSH Term	Description	Entries
D007525	Isoelectric Focusing	Electrophoresis in which a pH gradient is established in a gel medium and proteins migrate until they reach the site (or focus) at which the pH is equal to their isoelectric point.	Electrofocusing,Focusing, Isoelectric
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D011233	Precipitin Tests	Serologic tests in which a positive reaction manifested by visible CHEMICAL PRECIPITATION occurs when a soluble ANTIGEN reacts with its precipitins, i.e., ANTIBODIES that can form a precipitate.	Precipitin Test,Test, Precipitin,Tests, Precipitin
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D012321	DNA-Directed RNA Polymerases	Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).	DNA-Dependent RNA Polymerases,RNA Polymerases,Transcriptases,DNA-Directed RNA Polymerase,RNA Polymerase,Transcriptase,DNA Dependent RNA Polymerases,DNA Directed RNA Polymerase,DNA Directed RNA Polymerases,Polymerase, DNA-Directed RNA,Polymerase, RNA,Polymerases, DNA-Dependent RNA,Polymerases, DNA-Directed RNA,Polymerases, RNA,RNA Polymerase, DNA-Directed,RNA Polymerases, DNA-Dependent,RNA Polymerases, DNA-Directed
D012441	Saccharomyces cerevisiae	A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.	Baker's Yeast,Brewer's Yeast,Candida robusta,S. cerevisiae,Saccharomyces capensis,Saccharomyces italicus,Saccharomyces oviformis,Saccharomyces uvarum var. melibiosus,Yeast, Baker's,Yeast, Brewer's,Baker Yeast,S cerevisiae,Baker's Yeasts,Yeast, Baker
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular