Term
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Definition
Initially pry apart strands (in E.coli, it is DnaA)
-requires, but doesn't hydrolyze ATP |
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Term
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Definition
attaches and unwinds DNA, causing further strand separation
- with loader protein, dnaC
- Attaches to s.s. DNA, pushes other strand out of the way, must hydrolyze ATP
-Produces replication fork
- 1000bp/second |
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Term
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Definition
creates an RNA primer
- Needed to start okazaki fragments |
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Term
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Definition
attaches and starts replication
- attaches to sliding clamp, keeping it on the DNA, releases DNA POL when it hits d.s. DNA |
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Term
DNA Polymerase (E.coli)
POL I |
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Definition
Erases primer, and fills in gaps on lagging strand; DNA repair.
- Proofreads
- Has 5'->3' exonuclease activity
- 16 to 20 nucleotides/second
- Processivity: 3-200 nucleotides/enzyme dissociation |
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Term
DNA Polymerase (E.coli)
POL II |
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Definition
DNA repair
- Proofreads
- No Exonuclease activity
- 40 nucleotides/second
- Processivity: 1500 nucleotides/enzyme dissociation |
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Term
DNA Polymerase (E.coli)
POL III |
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Definition
Principal enzyme for DNA replication
- proofreads
- no exonuclease activity
- 250 to 1000 nucleotides/second
- Processivity: 500,000+ nucleotides/enzyme dissociation |
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Term
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Definition
| Can only create new DNA 5' to 3', which is easy for the leading strand. The lagging strand is synthesized in a discontinuous manner in runs of a few hundred to a few thousand nucleotides, called Okazaki fragments |
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Term
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Definition
| repairs breaks, restoring phosphodiester bond |
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Term
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Definition
| reduces the supercoiling stress caused by unwinding during replication |
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Term
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Definition
| resolves interlocked DNA strands, cuts 2 strands. Creates transient covalent bond |
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Term
| Antibiotics that affect TOPO II |
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Definition
Quinolones
Floroquinolones - ciprofloxacin, levofloxacin, norfloxacin, etc.
-Inactivate topo II, can't get the two circles apart = dead cells |
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Term
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Definition
Basic proteins that neutralize the acidic nature of DNA.
Removed during replication, then quickly replaced.
H1, H2A, H2B, H3, H4
Covalently modified (determines where it sits/acts) |
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Term
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Definition
One large H1 per nucleosome
Nucleosome is not a tight complex; it unfolds ("loosens") frequently |
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Term
| Selection of a particular site for starting replication depends on a number of factors: |
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Definition
Chromatin structure, histone acetylation
Local supercoiling of DNA
Positioning of DNA segment within nucleus
Transcription of nearby genes |
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Term
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Definition
| One strand in the telomere is longer than the other, and it is richer in guanine nucleotides. This strand loops back and pairs up with preceding DNA sequences in the same strand, forming G-quadruplexes -four coplanar guanine bases, linked by Hydrogen bonds |
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Term
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Definition
| Telomerase is needed because the lagging strand has difficulty in finishing its strand. A reverse transcriptase, takes a piece of RNA and back copies it to DNA |
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Term
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Definition
A DNA Polymerase Inhibitor:
- used against viral infections, causes premature chain termination. |
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Term
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Definition
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