MOLECULAR BIOLOGY AND pROTEIN sTRUCTURE
Central Dogma
DNA
Basics
DNA as Genetic Material
>
Fredrich Griffith (1928)
Avery, MacLeod, McCarty (1944)
Hershey and Chase (1952)
Erwin Chargaff
Watson and Crick (1953)
Rosalind Franklin
Semi-conservative Replication
>
Meselson & Stahl (1958)
DNA Replication
>
Origin of replication
Initiation and Unwinding
Primer Synthesis
DNA Polymerase
>
Arthur Kornberg
DNA Polymerase I
DNA Polymerase III
Leading and Lagging Strand
>
Okazaki Fragment
Termination
Repair Mechanisims
>
Mutations
DNA Repair Systems
>
Mismatch Repair
Nucleotide Excise Repair
Base-Excision Repair
Direct Repair
Eukaryotic DNA replication
Transcription
Prokaryotic Regulation
Eukaryotic Regulation
Initiation & Unwinding
The first major step for the
DNA Replication
to take place is the breaking of hydrogen bonds between bases of the two antiparallel strands
1st step of DNA replication to take place, is to break hydrogen bonds between bases of 2 antiparallel strand and separate the 2 strands.
Helicase
is the enzyme that splits the two strands.
The initiation point where the splitting starts is called "origin of replication".
The structure that is created is known as "
Replication Fork
".
Involves the assembly of a replication fork (bubble) at an origin of replication
Fork is generated by a complex of proteins
Major initiator protein is the dnaA protein (it binds to TTATCCACA sequence )
Recruits DNA helicase (dnaB) and DNA primase (dnaG) proteins.
Helicase bound by an inhibitor protein (dnaC), which is released to allow DNA binding at replication origin.
Helicase
→
begins to break hydrogen bonds & unwind DNA and also move the replication fork.
SSB proteins
→
stop the unwound DNA from rejoining (stabilise the exposed single-stranded DNA)
Topoisomerase (DNA Gyrase) → reduce the torsional strain caused by the unwinding of the double helix (relieves strain ahead of the replication fork.
Central Dogma
DNA
Basics
DNA as Genetic Material
>
Fredrich Griffith (1928)
Avery, MacLeod, McCarty (1944)
Hershey and Chase (1952)
Erwin Chargaff
Watson and Crick (1953)
Rosalind Franklin
Semi-conservative Replication
>
Meselson & Stahl (1958)
DNA Replication
>
Origin of replication
Initiation and Unwinding
Primer Synthesis
DNA Polymerase
>
Arthur Kornberg
DNA Polymerase I
DNA Polymerase III
Leading and Lagging Strand
>
Okazaki Fragment
Termination
Repair Mechanisims
>
Mutations
DNA Repair Systems
>
Mismatch Repair
Nucleotide Excise Repair
Base-Excision Repair
Direct Repair
Eukaryotic DNA replication
Transcription
Prokaryotic Regulation
Eukaryotic Regulation