Biomaterial Database

A hydrogen exchange study of Escherichia coli 5S RNA. 1981

J Ramstein, and V A Erdmann

Using the tritium Sephadex method, the number of exchangeable protons in E. coli 5S RNA and the kinetics of their exchange reactions have been measured at two different Mg++ concentrations (10(-2) M and 10(-3) M). A quantitative analysis of these results indicates the presence of two classes of protons exchanging with very different rates. The protons of the slow class, not seen in linear molecules of double helical RNA, exchange with a half-time of 0.6 hour and their exchange kinetics are independent of Mg++ concentration. Reduction of the Mg++ concentration from 10(-2) ot 10(-3) M, however, results in a decrease in the number of these exchangeable protons form 26 to 19. Neither the total number, nor the exchange kinetics of the fast protons are affected by this change in Mg++ concentration. Comparison of these results with those previously obtained with tRNA, suggests the presence of a Mg++ dependent tertiary structure in 5S RNA. The number of exchangeable protons obtained from extrapolation of the exchange curves (120 and 126 respectively for 10(-3) and 10(-2) M Mg++ concentration) are compared to the calculated number of exchangeable protons predicted by previous proposed structural models for E.Coli 5S RNA.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D011522	Protons	Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.	Hydrogen Ions,Hydrogen Ion,Ion, Hydrogen,Ions, Hydrogen,Proton
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
D006859	Hydrogen	The first chemical element in the periodic table with atomic symbol H, and atomic number 1. Protium (atomic weight 1) is by far the most common hydrogen isotope. Hydrogen also exists as the stable isotope DEUTERIUM (atomic weight 2) and the radioactive isotope TRITIUM (atomic weight 3). Hydrogen forms into a diatomic molecule at room temperature and appears as a highly flammable colorless and odorless gas.	Protium,Hydrogen-1
D012329	RNA, Bacterial	Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.	Bacterial RNA
D014316	Tritium	The radioactive isotope of hydrogen also known as hydrogen-3. It contains two NEUTRONS and one PROTON in its nucleus and decays to produce low energy BETA PARTICLES.	Hydrogen-3,Hydrogen 3