How many fragments will be obtained when lambda phage DNA is digested with EcoRI?
6 discrete fragments
Description/Preparation: The EcoRI digest of phage-DNA yields the 6 discrete fragments.
Why lambda DNA is used in restriction digestion?
Since the lambda genome is approximately 48,000 base pairs, each restriction enzyme will cut the DNA several times and generate restriction fragments of different sizes. In this activity, three separate samples of lambda DNA will be cut using three different restriction enzymes, and one sample will remain undigested.
How many EcoRI sites are there in lambda DNA?
six recognition sites
ABOUT THIS PRODUCT: The DNA from bacteriophage lambda is a well-characterized linear molecule containing six recognition sites for Eco RI (generating 5 fragments with distinct sizes and 2 fragments that are very close in size). In this experiment, Lambda DNA is digested by the Eco RI endonuclease.
Is lambda DNA a restriction enzyme?
The 12 nucleotide 5′ overhangs at the cos-ends of the linear Lambda DNA are the result of a cut by the enzyme terminase. This enzyme is encoded by Lambda itself and acts like a restriction enzyme during the replication of the phage DNA. It is an endonuclease specific for the cos-site in multimeric phage DNA.
How many fragments are produced by EcoRI?
Cutting with Eco RI will yield fragments of 1.5, 2, and 3.5 kilobases. Cutting with both Hin dIII and Pvu II will yield fragments of 1, 1.5, and 2 kilobases.
What is lambda DNA used for?
Lambda DNA (48,502 bp) may be used as a molecular weight size marker during nucleic acid gel analysis following digestion with a restriction enzyme (such as HindIII). Lambda DNA can also be used as a substrate in restriction enzyme activity assays.
How many fragments would result if the DNA above was digested with EcoRI?
Digesting with both EcoRI and HindIII, will yield 0.5, 1, and 1.5 kilobase fragments.
What does EcoRI cleave?
EcoRI (pronounced “eco R one”) is a restriction endonuclease enzyme isolated from species E. coli. It is a restriction enzyme that cleaves DNA double helices into fragments at specific sites, and is also a part of the restriction modification system.
Where does restriction enzyme EcoR1 cut DNA?
EcoR1 cuts DNA at the recognition sequence between the G and A nucleotides (see legend for Fig. 1) to produce a 16-bp fragment that remains attached to the microparticle surface and a 74-bp fragment free to diffuse into the bulk solution.
What is the function of lambda repressor?
The lambda repressor is a self assembling dimer also known as the cI protein. It binds DNA in the helix-turn-helix binding motif. It regulates the transcription of the cI protein and the Cro protein. The life cycle of lambda phages is controlled by cI and Cro proteins.
Where is lambda DNA from?
lysogen E.coli l cI857
The phage is isolated from the heat-inducible lysogen E. coli l cI857 S7. The DNA is isolated from the purified phage byphenol extraction and dialyzed against 10 mM Tris-HCl (pH 8.0), 1 mM EDTA.
What happens when the vector DNA is digested with EcoRI?
A plasmid vector is digested with EcoRI at a single site to produce two sticky ends. A sample of human DNA is also digested with EcoRI to produce pieces with the same sticky ends.
Where does restriction enzyme EcoRI cut DNA?
EcoRI cuts double stranded DNA at the sequence GAATTC, but note that this enzyme, like many others, does not cut in exactly the middle of the restriction sequence (Figure 8.4. 8). The ends of a molecule cut by EcoRI have an overhanging region of single stranded DNA, and so are sometimes called sticky-ends.
How does EcoR1 cleave DNA?
How does EcoRI cleave its recognition site on DNA? The two protein subunits of the EcoRl restriction enzyme interact symmetrically with the recognition site on DNA, so that each subunit is in position to cleave one strand of the DNA.
How does lambda repressor and Cro work?
Cro, a repressor protein of temperate bacteriophages (e.g. lambda [l], 434, P22), works in opposition to the phage’s repressor to control the genetic switch that determines whether a lytic or lysogenic cycle will follow infection.
What are lambda phage vectors?
Bacteriophages such as lambda phages can also be used as effective vectors for transferring recombinant DNA molecules into cells for cloning. A lambda phage is a bacteriophage that infects E. Coli cells. This phage, like any virus, readily undergoes two types of life cycles – the lytic cycle and the lysogenic cycle.
Is lambda DNA circular or linear?
Our lambda DNA is linear. We do not sell Lambda DNA in a circular form. Theoretically, it could be ligated to form circles but, due to its large size, it is difficult to achieve.
How does the lambda phage work?
Lambda phage is a non-contractile tailed phage, meaning during an infection event it cannot ‘force’ its DNA through a bacterial cell membrane. It must instead use an existing pathway to invade the host cell, having evolved the tip of its tail to interact with a specific pore to allow entry of its DNA to the hosts.
Which type of ends are produced by EcoRI?
EcoRI creates 4 nucleotide sticky ends with 5′ end overhangs of AATT. The nucleic acid recognition sequence where the enzyme cuts is G↓AATTC, which has a palindromic, complementary sequence of CTTAA↓G. Other restriction enzymes, depending on their cut sites, can also leave 3′ overhangs or blunt ends with no overhangs.