Recombinant DNA Molecules

Plasmid DNA molecule with human DNA insert (recombinant DNA molecule)... 

Fig. 24.3 The construction of a chimeric (or recombinant) DNA molecule hy joining together two DNA fragments produced by cleavage of different parental DNA molecules with the same restriction endonuclease.

Graham, M., Smith, T.S., Munn, E.A. and Newton, S.E. (1993) Recombinant DNA molecules encoding aminopeptidase enzymes and their use in the preparation of vaccines against helminth infections. Patent No. WO 93/23542. 

A recombinant DNA molecule is a novel DNA sequence formed by in vitro combination of two non-homologous DNA molecules (or fragments) giving rise to genetic material. 

A recombinant DNA molecule from Rhodococcus origin encoding a biocatalyst capable of desulfurizing a fossil fuel. 

A BDS method using a transformed microorganism containing a recombinant DNA molecule of Rhodococcus origin. This transformed microorganism expresses a BDS-active biocatalyst. (Use in BDS of the biocatalyst protected in Refs. [37-39])... 

The discovery that the rate of reaction of the desulfurization of fossil fuels is enhanced by the addition of a flavoprotein to the biocatalyst was then claimed in the other two family patents. So, the patents are related to the use of a flavoprotein, particularly FMN reductase, in addition to the biocatalytic material for increasing the rate of desulfurization. In the World patent, ten more claims were allowed, compared to the US issued patent. The excess claims include a set of dependant claims in which the microorganism containing the recombinant DNA molecule is considered. However, in the invention a two-step process is stated, it is just the contact between the fossil fuel with an aqueous phase containing a biocatalyst and a rate-enhancing amount of a flavoprotein. There is no indication whatsoever on how much that amount could be. 

Recombinant DNA molecules A combination of DNA molecules of different origin that are joined using recombinant DNA technologies. 

Generating a RECOMBINANT-DNA molecule using restriction enzymes to generate ends that can be joined in a specific fashion. 

Cloning would not be possible without restriction enzymes. DNA chains with a "sticky" end act like molecular "Velcro", thereby enabling two pieces of DNA with complementary nucleotide sequences to be joined together. The linking of the DNA strands is brought about by the enzyme DNAligase which permanently joins the assembled DNA sequences with covalent bonds, thereby producing a recombinant DNA molecule. 

The next stage is to ensure that the recombinant DNA molecule is copied by the enzymes which s)mthesize nucleic acids. These DNA and RNA polymerases synthesize an exact copy of either DNA or RNA from a pre-existing molecule. In this way the DNA polymerase duplicates the chromosome before each cell division such that each daughter cell will have a complete set of genetic instructions which are then passed to the newly formed RNA by RNA polymerase. While both DNA and RNA polymerase require a preformed DNA template, some viruses (such as HIV) have an RNA genome. To duplicate that genome, and incorporate it into a bacterial or mammalian cell, the viruses encode a reverse transcriptase enzyme which produces a DNA copy from an RNA template. 

Herbert Boyer and Stanley Cohen construct first recombinant DNA molecule and reproduce... 

Similar methods were used soon after in the laboratory of Paul Berg to join DNA segments from simian virus 40 (SV40) to DNA derived from bacteriophage A, thereby creating the first recombinant DNA molecule with DNA segments from different species. 

Replicative transposons. In 1979 Shapiro proposed the mechanism illustrated in Fig. 27-31 for replicative transposons. The two inversely repeated segments (green) at the ends of the transposon are aligned with the recipient DNA whose ends are labeled C and D. In fact, the recombining DNA molecules must be supercoiled.1 613 Staggered cuts are made in the recipient DNA at points a and b, which are 5, 9, or 11 bp apart, depending upon the specific recombinase. Nicks are also made in the transposon ends. The 3 ends from the transposon are resealed... 

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