The molecular size and conformation of chloroplast (ct-) DNA has been studied by renaturation kinetics and electron microscopy. Ct-DNA of buoyant density 1.698 f 0.001 g per cm3 showed a T,, of 84” and a homogeneous melting pattern. Denatured and sheared c&DNA renatured as a single kinetic class with no suggestion of repeating sequences. Ct-DNA is found to have a molecular weight of 95 x lo6 by...

Background: Aptamers are single stranded DNA (ssDNA) or RNA molecules. The potential of aptamers for binding to the different targets has made them be widely used as the preferred diagnostic and therapeutic tools. DNA aptamers present several advantages over the RNA oligonucleotides due to their higher stability, easier selection, and production. Selection of DNA aptamers which...

From a tandem duplication mutant of phage P2, triplication, quadruplication and pentuplication forms were derived. They were recognized by decreased virion heat stability resulting from the increase in DNA content, and were confirmed by electron microscope heteroduplex mapping. These forms of partially repeated DNA are quite stable in P2 because of the low level of recombination typical of this...

OBJECTIVES The present study was designed to systematically characterize the denaturation and the renaturation of double stranded DNA (dsDNA), which is suitable for DNA hybridization. METHODS A series of physical and chemical denaturation methods were implemented on well-defined 86-bp dsDNA fragment. The degree of each denaturation was measured and the most suitable denaturation method was de...

Histones isolated from several sources, either singly or in combination promote the renaturation of complementary single strands of DNA, as measured by the acquisition of resistance to S1 nuclease. The reaction is rapid (T1/2 less than 1 min), and is stoichiometric rather than catalytic. Renaturation is stimulated by Mg2+, Mn2+, and Ca2+, but is strongly inhibited by Zn2+. Crude extracts of ear...

The renaturation of complementary DNA strands by the recA protein of Escherichia coli has been found to exhibit the following features. (i) Optimal renaturation occurs at recA protein levels below that required to saturate the DNA strands; saturating amounts of recA protein significantly reduce the rate of reaction. (ii) The reaction proceeds in the absence of a nucleotide cofactor but is marke...

We consider a new model which consists of DNA together with RNA. Here we assume that is from mammal or bird but RNA comes virus. To study thermodynamic properties this use methods statistical mechanics, namely, the theory Gibbs measures. these measures to describe phases (states) DNA-RNA system. Using Markov chain (corresponding measure) give conditions (on temperature) renaturation.

The refolding and reoxidation of fully reduced and denatured chymotrypsinogen A have been studied in the presence of low concentrations of guanidine HCl or urea. Renaturation yields of 60 to 70% were observed when the reoxidation was facilitated by mixtures of reduced and oxidized glutathione. Refolding occurred within a narrow range of denaturant concentration (1.0 to 1.3 M guanidine HCl and 2...

Protein sequences are believed to have been selected to provide the stability of, and reliable renaturation to, an encoded unique spatial fold. In recently proposed theoretical schemes, this selection is modeled as “minimal frustration,” or “optimal energy” of the desirable target conformation over all possible sequences, such that the “design” of the sequence is governed by the interactions be...

We have developed an assay for chaperone-mediated protein renaturation using thermally denatured Firefly luciferase. Dilution of denatured luciferase (> 99% loss of activity) into reticulocyte lysate typically results in recovery of 5-15% activity. Addition of an ATP-regenerating system increases yields to > 60%, while heat shock or the addition of denatured proteins inhibits the chaperoning ac...