Sizing, nucleic acid

All forms of life—animal, plant and even bacterial—are susceptible to infection by viruses. Three main properties distinguish viruses from their various host cells size, nucleic acid content and metabolic capabilities. 

In conclusion, NMR has become a routine and reliable technique for the determination of average solution structures of moderately sized nucleic acids of up to about 30-40 nt the challenges for structure determination increase more than linearly as molecular size increases. It is expected that development of experimental and computational techniques will lead to rapid progress in two directions a better understanding of flexibility and dynamics of nucleic acids in solution,342 343 and increasing the size limit of nucleic acids amenable to structure determination.254,259,261,265,275,296... 

The experimental studies on biopolymer structures are increasingly supplemented by computational approaches. First, it has to be realized that computation is a sine qua non for experimental structure determination by diffraction methods and NMR spectroscopy themselves. In addition, independent computational studies can provide useful information on structure and dynamics of biopolymers not accessible, at least currently, by experiments. With regard to base poiyads there are three fields that have to be mentioned here primarily quantum-chemical studies of nucleic building blocks, MD simulations of medium-sized nucleic acids and structural bioinformatics. 

Agarose and polyacrylamide gels are the most common used matrixes for the separation of nucleic acids. Small size nucleic acids (less than 2 kb) are usually separated on agarose gels. For high resolution and for the separation of large DNA molecules polyacrylamide gel is recommended. Polyacrylamide gels are also used for the separation of proteins. 

Fig. 2 shows the fractionation of oligo (rA) with chain lengths of 3 to 37 nucleotides on TSK-DEAE 5PW. Similar results have been reported for Nucleogen DEAE 60 [16] and MONO-Q [17]. As an example for lEC separation of medium-sized nucleic acids, the elution profile of a crude plant RNA extract on Nucleogen DEAE 500 is shown in Fig. 3. A comparable resolution was obtained on TSK-DEAE 5PW although a slower elution was necessary [18]. The resin with the...

Staining Applications Nucleic acidsp cells Biological Applications Nucleic acid hybridization detecting nucleic acidsp cells nucleic acid fingerprinting nucleic acid fragment sizing nucleic acid amplification ... 

In this book, we concentrate largely on methods for the computer manipulation of small and medium-sized molecules, molecules of up to a few hundred or thousand atoms. We do this to develop an understanding of the methods available for the processing of information on chemical compounds and reactions. However, many of these methods can also be applied to macromolecules such as proteins and nucleic acids. 

Uracil is used more effectively, in nucleic acid synthesis within a rat hepatoma than in normal liver. This observation appears to have stimulated the synthesis of 5-fluorouracil (1027) as an antimetabolite mainly because the introduction of a fluorine atom involves a minimal increase in size. In the event, 5-fluorouracil did prove to have antineoplastic activity and it is now a valuable drug for treatment of tumors of the breast, colon or rectum, and to a lesser extent, gastric, hepatic, pancreatic, uterine, ovarian and bladder carcinomas. As with other drugs which interfere with DNA synthesis, the therapeutic index is quite low and great care is required during treatment (69MI21301). 

Sephadex. Other carbohydrate matrices such as Sephadex (based on dextran) have more uniform particle sizes. Their advantages over the celluloses include faster and more reproducible flow rates and they can be used directly without removal of fines . Sephadex, which can also be obtained in a variety of ion-exchange forms (see Table 15) consists of beads of a cross-linked dextran gel which swells in water and aqueous salt solutions. The smaller the bead size, the higher the resolution that is possible but the slower the flow rate. Typical applications of Sephadex gels are the fractionation of mixtures of polypeptides, proteins, nucleic acids, polysaccharides and for desalting solutions. 

Most biological polymers, such as proteins and nucleic acids and some synthetic polymers, have relatively inflexible chains. For rigid particles, the size is no longer of predominant importance, because the polymer chain is no longer in the form of a flexible random coil instead, shape becomes an important parameter. Following are some theoretical proposals for the estimation of the shape factor p from the viscosity measurement (table 4). The term f/fo is sometimes denoted as p, Perrin constant. 

Gorin has extended this analysis to include (1) the effects of the finite size of the counterions in the double layer of spherical particles [137], and (2) the effects of geometry, i.e. for cylindrical particles [2]. The former is known as the Debye-Huckel-Henry-Gorin (DHHG) model. Stigter and coworkers [348,369-374] considered the electrophoretic mobility of polyelectrolytes with applications to the determination of the mobility of nucleic acids. 

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