Plegable biología molecular
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Transcript of Plegable biología molecular
• Ori recognition by helicases
• Fork formation
Step 1
•Maintenance of fork
•Action on each strand of SSDBP
Step 2 •synthesis primer , the gaps are filled by polymerase
•joined by DNA ligase
Step 3
• leading strand is copied continuously
• the lagging strand is copied Okazaki fragments subsequently joined by ligase
Step 4
• Relax of supercoiling by topoisomerases
Step 5 • Finish of replication
Step 6
Ribonucleotide reductase (RNR) catalyzes the reduction of
ribonucleotides to the corresponding
deoxyribonucleotides, which are used as building blocks for DNA
replication and repair. This process is tightly regulated via two
allosteric sites, the specificity site (s-site) and the overall activity site
(a-site).
This four-in-one machine takes on four different shapes depending on
whether the RNA nucleotide is A, G, C, or U. It sends out DNA's four, A,
G, C, and T with the appropriate sugar
deoxyribose instead of ribose (replacing an OH radical with a hydrogen
atom, a "reduction" reaction).
RNR is a multi-tool The effectors, the substrates
and the active sites are all closely matched to the
operation at hand, whether generating more
DNA building blocks or regulating their supply in
the cell.
An intricate interplay between gene activation,
enzyme inhibition, and protein degradation
regulates, together with the allosteric effects, enzyme activity and
provides the appropriate amount of
deoxynucleotides for DNA replication and repair.
Enzyme that Maintains DNA Building Blocks
A lot of new building blocks are needed for repair and replication.
I can see why this enzyme is essential for a cell when it divides
or suffers stress.
They showed that this enzyme acts as a switch then clamps down on the substrate and
"reduces" it by replacing the oxygen radical with a hydrogen.
When released, the DNA building block is ready for use, the
effector switches the machine off, and the enzyme is ready for the
next operation.
I UNDERSTOOD
• “Deoxyribonucleotides are generated from ribonucleotides, which are the building blocks for RNAs -- molecules that perform many important roles in gene expression. RNR, which catalyzes the conversion of ribonucleotides to deoxyribonucleotides, is an evolutionarily ancient enzyme that may have been responsible for the conversion of the earliest life forms, which were based on RNA, into DNA-based organisms”
Drennan says.
Student’s observation
It is shocking how science has advanced by creating an enzyme that carries out the reduction of ribonucleotides to deoxyribonucleotides to ensure proper DNA replication
Newswise — STONY BROOK, NY, February 10, 2016 — A team of scientists led by Stony Brook University
biochemist Huilin Li, PhD,
•That “Each rocking motion could nudge the DNA strands apart and move the helicase along the double helix in a linear fashion”
THEY CHECKED
•The scientists produced high-resolution images of the helicase using a technique known as cryo-electron microscopy (cryo-EM).
THROUGH
HELICASE
•They wanted to know the structure of the helicase and thereby realized that the helicase can still function even When the ATP hydrolysis activity of some, but not all , of the components is knocked out by mutation
Student’s observation
Nowdays is very important to know the mechanism of DNA replication because we can understand mutations and even stop them. They studied in this research helicase which is a key protein for initiation of replication.
Both investigations seeking to Understand the process of DNA replication to find solutions to
the Changes That Occur at this time of the formation of a new
cell
MEDICAL UTILITY
•DNA replication is essential for life , as it allows genetic information is passed from a mother cell to daughter cells . It is also important that the split may have mutations
MEDICAL UTILITY
knowing the process of DNA replication possibly we can do target therapy against cancer or other diseases.
MEDICAL UTILITY
BIBLIOGRAPHY
Martinez Sanchez, Lina Maria. Biologia molecular.7.ed.Medellin: UPB.Fac.Medicina.
-Newswise. February 10 2016. Mechanism That Unwinds DNA May Function Similar to an Oil Rig “Pumpjack”. Retrieved February 12 2016.http://www.newswise.com/articles/mechanism-that-unwinds-dna-may-function-similar-to-an-oil-rig-pumpjack
-Mit news. January 16 2016. An "Exquisitely Designed" Enzyme that Maintains DNA Building Blocks. Retrieved February 12 2016.http://www.evolutionnews.org/2016/01/an_exquisitely102401.html
-Gen news. February 9 2016. Structural Study Points to New DNA Replication Mechanism. Retrieved February 12 2016 .-http://www.genengnews.com/gen-news-highlights/structural-study-points-to-new-dna-replication-mechanism/81252345/