DNA ligase is an enzyme that repairs irregularities or breaks in the backbone of double-stranded DNA molecules. It has three general functions: It seals repairs in the DNA, it seals recombination fragments, and it connects Okazaki fragments (small DNA fragments formed during the replication of double-stranded DNA). DNA ligase functions by forming a bond between the end of a “donor” nucleotide and the end of an “acceptor” nucleotide.Know More
There are two main types of DNA ligase — the first is found only in prokaryotic cells (cells with no nucleus, such as bacteria). The second is found in eukaryotic cells (cells with a nucleus, like those of plants and animals) as well as in viruses and bacteriophages. Furthermore, mammals have four subtypes of ligases that vary in their function; DNA ligase III, for example, contains a DNA repair protein, called XRCC1, that seals the break in the DNA strand that occurs during nucleotide excision repair. In general, eukaryotic DNA ligases are much larger than their prokaryotic counterparts; the smallest DNA ligase is produced by the bacteriophage T7.
Because DNA ligase plays such an important role in assisting with DNA repair and replication, it is an important component of genetic recombination experiments, including cloning.Learn more about Molecular Biology & DNA
The powerful enzyme DNA helicase unwinds the double strands of DNA by breaking the bonds between each of the complementary bases. These bases are held together by strong hydrogen bonds, but in breaking these, DNA helicase creates two single-stranded DNA molecules.Full Answer >
The primary function of DNA is to send the instructions needed for the development, survival and reproduction of living organisms. DNA contains information required to create proteins, and proteins are used to complete specific functions. Proteins are complex molecules that serve different functions and provide physical characteristics to organisms. To accomplish different functions, DNA sequences are transformed into messages that are used to produce proteins.Full Answer >
The enzyme DNA helicase unzips the DNA double helix to allow it to replicate. DNA helicase has a rotation speed of 10,000 rotations per minute and moves ahead of the replication fork. It continuously unwinds the DNA strands to allow DNA polymerase to attached new nucleotide strands.Full Answer >
The enzyme that catalyzes the elongation of a DNA strand is DNA polymerase, according to the RCSB Protein Data Bank. This enzyme adds to the growing DNA molecule by adding nucleotide bases. DNA polymerase only makes one mistake every billion bases it adds, making this enzyme extremely accurate.Full Answer >