Tuesday, 10 July 2012
Wednesday, 4 July 2012
DNA Replication Enzyme
Prime Replication Enzymes
There are many enzymes involved in DNA replication due to the complex nature of the whole process. Here are the main enzymes and their functions in eukaryotic cells, during cell division.
Helicase
DNA replication begins at places called origins, within the DNA molecule and the creation of replication forks. The process of strand separation is made possible because of the enzyme Helicase which separates the two strands using the energy that is derived from ATP hydrolysis.
DNA Primase
One of the most crucial enzymes is DNA Primase. After the DNA strands are separated, to begin the creation of new DNA molecules, through addition of complementary bases to the templates, a short RNA segment, called a 'primer' is required. These primers are synthesized by DNA primase enzymes, thus initiating the DNA replication process. That is why DNA Primase is one of the most important DNA replication enzyme.
DNA Polymerase
The most important enzymes, that carry out the main task of aligning the complementary bases with template strands of 'unzipped' DNA, are the DNA polymerases. They are a large family of enzymes that carry out the task of adding complementary base nucleotides by reading the template strands. Besides the task of elongating the DNA molecule, they also carry out DNA proofreading and repair.
Exonuclease (DNA Polymerase I)
The main function of Exonucleases like DNA polymerase I is to remove the RNA primer segments from the template strand. It is always involved in the 'Search and Remove' operation of RNA primers.
DNA Ligase
While Helicase works to unwind the DNA molecule, DNA Ligase is the DNA replication enzyme that binds the DNA fragments together by addition of phosphates in the gaps that remain in the phophate-ribose sugar backbone.
These enzymes are the crucial parts of replication assembly line. The precision with which every single segment of the complementary strand is aligned is mind-boggling. No man-made assembly line can match the efficiency, detailing and brilliance of the DNA replication mechanism that makes biological inheritance possible.
There are many enzymes involved in DNA replication due to the complex nature of the whole process. Here are the main enzymes and their functions in eukaryotic cells, during cell division.
Helicase
DNA replication begins at places called origins, within the DNA molecule and the creation of replication forks. The process of strand separation is made possible because of the enzyme Helicase which separates the two strands using the energy that is derived from ATP hydrolysis.
DNA Primase
One of the most crucial enzymes is DNA Primase. After the DNA strands are separated, to begin the creation of new DNA molecules, through addition of complementary bases to the templates, a short RNA segment, called a 'primer' is required. These primers are synthesized by DNA primase enzymes, thus initiating the DNA replication process. That is why DNA Primase is one of the most important DNA replication enzyme.
DNA Polymerase
The most important enzymes, that carry out the main task of aligning the complementary bases with template strands of 'unzipped' DNA, are the DNA polymerases. They are a large family of enzymes that carry out the task of adding complementary base nucleotides by reading the template strands. Besides the task of elongating the DNA molecule, they also carry out DNA proofreading and repair.
Exonuclease (DNA Polymerase I)
The main function of Exonucleases like DNA polymerase I is to remove the RNA primer segments from the template strand. It is always involved in the 'Search and Remove' operation of RNA primers.
DNA Ligase
While Helicase works to unwind the DNA molecule, DNA Ligase is the DNA replication enzyme that binds the DNA fragments together by addition of phosphates in the gaps that remain in the phophate-ribose sugar backbone.
These enzymes are the crucial parts of replication assembly line. The precision with which every single segment of the complementary strand is aligned is mind-boggling. No man-made assembly line can match the efficiency, detailing and brilliance of the DNA replication mechanism that makes biological inheritance possible.
**Difference Between Nucleotide & Nucleoside
A nucleoside (with an s) is a nitrogenous base covalently
attached to a (ribose or deoxyribose) sugar but does not have a phosphate group
attached.
A nucleotide (with a t) consists of a nitrogenous base, a sugar, and a
phosphate group.
So, a nucleotide is a "nucleoside mono-phosphate" or a nucleoside with a phosphate group attached.
A nucleotide (with a t) consists of a nitrogenous base, a sugar, and a
phosphate group.
So, a nucleotide is a "nucleoside mono-phosphate" or a nucleoside with a phosphate group attached.
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