Make molecular-level microscopic drawings for each of the following. Show the differences between a gaseous mixture that is a homogeneous mixture of two different compounds, and a gaseous mixture that is a homogeneous mixture of a compound and an element. Show the differences among a gaseous element, a liquid element, and a solid element.
RNA and swapped hybrid substrates, were used to probe structural features of the PPT that contribute to its specific recognition and processing by reverse transcriptase RT. These observations, together with the fact that the sites are correctly spaced to allow interaction with residues in the ribonuclease H RNase H active site and thumb subdomain of the p66 RT subunit, suggest that despite the long cleft employed by RT to make contact with nucleic acids substrates, these sites provide discrete binding units working in concert to determine not only specific PPT recognition, but also its orientation on the hybrid structure.
These identical stretches of genomic RNA are not affected by template degradation associated with minus-strand synthesis. Catalyzed by the RNase H function of RT, these hydrolytic events must be completed with high precision and specificity to produce proviral DNA of well-defined ends.
The fact that imprecise PPT processing leads to impaired integration provides a powerful motivation for investigating the structural determinants of RNase H activity as potential targets for new antiviral strategies 4—6.
In vitro studies have demonstrated that single-base substitutions induce only minor variations in the PPT cleavage pattern, suggesting that its structure is recognized as a whole by RT 7— High-resolution structural analysis has been reported for RNA: DNA duplexes covering different sections of the PPT sequence and contiguous regions Figure 1revealing significant deviations from typical hybrid structures with intermediate characteristics between canonical A- and B-type double helices 11— Constructs comprising the rA: Minor groove compression was also observed in the crystal structure of a complex between RT and a RNA: DNA substrate extending farther upstream 17which also displayed an unusual pattern of weakly paired, unpaired and mispaired bases Figure 1.
Chemical probing experiments performed in the absence of protein demonstrated that these pairing anomalies constitute an intrinsic characteristic of the PPT and not the direct result of RT binding The hypothesis that these unique structural features may serve as specific recognition sites prompted further studies to determine the effects of base-pairing and substrate geometry on PPT cleavage specificity, which enabled mapping of motifs necessary for proper positioning of the RNase H catalytic site onto the PPT-U3 junction Figure 1 19— Indicated are regions for which high-resolution structures are available and their relationship with the sequence employed in this study.
In this report, the interactions between non-covalent probes selected from different classes of nucleic acid binders and a series of PPT substrates were assessed using direct infusion electrospray ionization ESI 2425 and Fourier transform ion cyclotron resonance FTICR 2627 mass spectrometry.
Taking advantage of the inherently low energy afforded by this ionization technique to assess the stoichiometry and binding affinity provided by small molecule ligands 28—30we recently probed the specific interactions between the nucleocapsid NC domain of Gag and isolated RNA stemloops of the HIV-1 packaging signal 31 We have now implemented this approach to evaluate the ability of archetypical ligands to form stable complexes with PPT, determine their binding modes and identify their specific sites on the duplex structure.
Selected interactions were further investigated using high-resolution nuclear magnetic resonance NMR spectroscopy to confirm the stoichiometry and position of putative binding sites.
Isothermal titration calorimetry ITC was finally employed to assess the stability of different PPT complexes and obtain the thermodynamic characteristics of their binding equilibria. The observed interactions are discussed in the context of structural features of the PPT that may guide selective RT processing to create the plus-stand primer from within the viral RNA genome.
Desolvation temperature, skimmer voltage and other source parameters were optimized to allow for the observation of intact RNA non-covalent complexes, as previously described 31— Each analysis was performed a minimum of three times and only representative spectra were shown.solution appears in the Solutions Guide, as found on PowerLecture.
Questions. Chapter 3 Stoichiometry. The limiting reactant is the one with the higher molar mass.
A is the limiting reactant because you need 6 moles of A; and have 4 moles. * a substance that dissolves in water to form a solution that conducts electricity non-electrolyte *a substance that dissolves in water to form a solution that doesn't conduct electricity.
In designing a solution stoichiometry experiment for her class to perform, a chemistry teacher wants mL of M iron(III) chloride solution to react completely with an excess of M sodium carbonate solution.
Molar Mass 84 Learning to Solve Problems 87 Percent Composition of Compounds 88 Determining the Formula of a Compound 90 Chemical Equations 97 Balancing Chemical Equations 99 Stoichiometric Calculations: Amounts of Reactants and Products Types of Chemical Reactions and Solution Stoichiometry,” directly after the chapter on chemical.
was used as a solvent with a molar ratio salt/ligand of 1/4. and also because the dilution of solution b into solu- tion c has no thermal effect. Table 5 presents the values. specting the stoichiometry of the complex (solution b);.
Chapter 3- Formulas, Equations, and urbanagricultureinitiative.com - Download as PDF File .pdf), Text File .txt) or read online. How many grams of HCl are in mL of a M HCl solution? Solution Stoichiometry If solutions are described in terms of volumes and concentration we can still do stoichiometry: Mass Molar mass Moles of A Volume of Solution.