Engineering restriction enzymes

Johnston APR, Lee L, Wang Y, et al. (2009) Controlled degradation of DNA capsules with engineered restriction-enzyme cut sites. Small 5 1418-1421... 

The polymerase chain reaction (PCR) is an important procedure in genetic engineering that allows any DNA segment to be replicated (amplified) without the need for restriction enzymes, vectors, or host cells (see p. 258). However, the nucleotide sequence of the segment has to be known. Two oligonucleotides (primers) are needed, which each hybridize with one of the strands at each end of the DNA segment to be amplified also needed are sufficient quantities of the four deoxyribonucleo-side triphosphates and a special heat-tolerant DNA polymerase. The primers are produced by chemical synthesis, and the polymerase is obtained from thermostable bacteria. 

Figure 1.4 Engineering of a bacterium with a plasmid vector is a useful technique in biotechnology. Restriction enzymes are used to cut both foreign DNA and plasmid DNA, which are then joined together using DNA ligase and inserted into bacteria. The bacteria can then reproduce, expressing the modified DNA.

Horton, R M., Hunt, H. D., Ho, S N., Pullen, J K., and Pease, L R. (1989) Engineering hybrid genes without the use of restriction enzymes, gene splicing by overlap extension. Gene 77, 61-68... 

The restriction enzymes and hybridomas enabled new types of pharmaceutical products The developments associated with restriction enzymes (facilitate genetic engineering) and hybridomas (produce monoclonal antibodies) opened up vistas for a new range of potential products. Isolated from humans directly, these can now be produced in microorganisms or cell culture, and be used in large concentrations to enhance the body s ability to fight heart disease, cancer, and viral infections against which most antibiotics have little or no effect. 

DNA ligase repairs broken DNA by joining two nucleotides in a DNA strand. It is commonly used in genetic engineering to do the reverse of a restriction enzyme that is, to join together complementary restriction fragments. While sticky ends allow two complementary restriction... 

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