Conformational changes of transfer ribonucleic acid. pH phase diagram under acidic conditions

Biochemistry ◽  
1974 ◽  
Vol 13 (13) ◽  
pp. 2771-2775 ◽  
Author(s):  
Minou Bina-Stein ◽  
Donald M. Crother
Keyword(s):  
Phase Diagram ◽  
Conformational Changes ◽  
Ribonucleic Acid ◽  
Acid Ph ◽  
Acidic Conditions

scholarly journals Role of conformational heterogeneity in ligand recognition by viral RNA molecules

2021 ◽  
Author(s):  
Lev Levintov ◽  
Harish Vashisth
Keyword(s):  
Conformational Changes ◽  
Ribonucleic Acid ◽  
Viral Rna ◽  
Ligand Recognition ◽  
Conformational Heterogeneity ◽  
Rna Molecules ◽  
Environmental Stimuli

Ribonucleic acid (RNA) molecules are known to undergo conformational changes in response to various environmental stimuli including temperature, pH, and ligands. In particular, viral RNA molecules are a key example...

scholarly journals The Effects of Salts on the Stability of the Collagen Helix Under Acidic Conditions

1968 ◽  
Vol 21 (4) ◽  
pp. 821 ◽  
Author(s):  
Anne FW oodlock ◽  
BS Harrap
Keyword(s):  
Thermal Stability ◽  
Carboxyl Groups ◽  
Neutral Ph ◽  
Acid Ph ◽  
Helix Stability ◽  
Acidic Conditions ◽  
Anions And Cations ◽  
The Stability ◽  
Thermal Stability Of ◽  
Positively Charged

In the acid pH region, the relative effects of various salts on the thermal stability of the collagen helix are quite different from their effects at neutral pH. The magnitude of the decrease in thermal stability brought about by the salts studied depends mainly on the nature and concentration of the anion and very little on the nature of the cation, whereas at neutral pH the nature of both anions and cations affects the collagen helix stability, the effects of the two ions being roughly additive. The magnitude of the effect of salts at acid pH is much greater than that at neutral pH whereas for a non-ionized denaturant, urea, the magnitudes at both neutral and acid pH are similar. The data are discussed in terms of possible interactions between salts and the positively charged protein with particular consideration of the effects of salts on the pKa of protein carboxyl groups.

scholarly journals Fluoride Release from Fluoride Varnishes under Acidic Conditions

2014 ◽  
Vol 39 (1) ◽  
pp. 35-39 ◽  
Author(s):  
F Lippert
Keyword(s):  
Citric Acid ◽  
Artificial Saliva ◽  
Fluoride Varnish ◽  
Laboratory Research ◽  
Fluoride Release ◽  
Acidic Solutions ◽  
Acid Ph ◽  
Opposite Behavior ◽  
Acidic Conditions

Objective: The aim was to investigate the in vitro fluoride release from fluoride varnishes under acidic conditions. Study design: Poly(methyl methacrylate) blocks (Perspex, n=3 per group) were painted with 80±5 mg fluoride varnish (n=10) and placed into artificial saliva for 30min. Then, blocks were placed into either 1% citric acid (pH 2.27) or 0.3% citric acid (pH 3.75) solutions (n=3 per solution and varnish) for 30min with the solutions being replaced every 5min. Saliva and acid solutions were analyzed for fluoride content. Data were analyzed using three-way ANOVA (varnish, solution, time). Results: The three-way interaction was significant (p>0.0001). Fluoride release and release patterns varied considerably between varnishes. Fluoride release in saliva varied by a factor of more than 10 between varnishes. Some varnishes (CavityShield, Nupro, ProFluorid, Vanish) showed higher fluoride release in saliva than during the first 5min of acid exposure, whereas other varnishes (Acclean, Enamel-Pro, MI Varnish, Vella) showed the opposite behavior. There was little difference between acidic solutions. Conclusions: Fluoride release from fluoride varnishes varies considerably and also depends on the dissolution medium. Bearing in mind the limitations of laboratory research, the consumption of acidic drinks after fluoride varnish application should be avoided to optimize the benefit/risk ratio.

scholarly journals Chemical modification as a probe of conformational changes in transfer ribonucleic acid on aminoacylation

1978 ◽  
Vol 171 (3) ◽  
pp. 601-606
Author(s):  
M Lowdon ◽  
J P Goddard
Keyword(s):  
Escherichia Coli ◽  
Chemical Modification ◽  
Conformational Change ◽  
Conformational Changes ◽  
Ribonucleic Acid ◽  
Previous Evidence ◽  
Base Modification ◽  
Trna Species

Treatment of Escherichia coli CA265 phenylalanyl-tRNA with 3M-NaHSO3, pH6.0, at 25 degrees C resulted in modification of four bases and in the deacylation of the charged tRNAphe. The similarity of the rates of base modification and of the deacylation of the phenylalanyl-tRNA permitted the isolation of partially modified phenylalanyl-tRNAphe and partially modified deacylated tRNAphe. The sites and extents of base modification in these fractions were determined and found to be the same as those in uncharged tRNAphe modified under identical conditions. These findings are discussed in relation to previous evidence for and against a conformational change in tRNA on its aminoacylation. The methods described should prove adaptable to study of other aminoacyl-tRNA species.

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