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.

What are cos sites in phage λ What is their significance?

The cos site circularizes the DNA in the host cytoplasm. In its circular form, the phage genome, therefore, is 48,502 base pairs in length. The lambda genome can be inserted into the E. coli chromosome and is then called a prophage.

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.

What is the purpose of lambda DNA?

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.

What are cos sites?

The cos site represents the junction between two genomes in a concatemer and serves as the packaging initiation site. Unlike the pac sequences of viruses that use the head-full packaging mechanism, cos also serves as a specific packaging termination sequence.

What is lambda in sequencing?

Lambda is a medium size E. The DNA molecule of 48502 basepairs is linear and except for the extreme ends double-stranded. At each end the 5′ strand overhangs the 3′ strand by 12 bases. The sequences of the ends are complementary.

What are lambda vectors?

Bacteriophage lambda has been in use as a cloning vector for over 25 years, and has been used extensively as an expression vector. The efficiency of packaging and infection, and the simplicity of plaque screening are advantages of lambda as a cloning vector.

What is cos site why it is important?

What is the restriction site for EcoRI?

EcoRI ligation. The restriction endonuclease enzyme EcoRI recognizes the ssDNA sequence 5′-GAATTC’-3, and introduces a single-strand cut between the G & A nucleotides. This recognition site is a palindrome: the opposite strand also reads 5′-GAATTC’-3 and will be cut in the same manner.

How do I count the number of restrictions sites?

First, work out the frequency of occurrence of the restriction site as 1-in-x bases, as explained in the example for the Intermediate level calculation. Then take the size of the DNA in kb (kilobases) and multiply by 1000 to get the size in bases. Divide this by x and round to the nearest whole number.

Where can I find restriction maps for DNA sequences?

Detailed restriction maps can be found on DNA sequences and maps. The sites listed in these tables were identified by computer analysis of published sequences. Although we have tried to ensure their accuracy, the sites have not necessarily been confirmed by experimentation.

Where can restriction endonuclease sites be found?

The table below summarizes the frequencies with which restriction endonuclease sites occur in commonly used DNA molecules. Detailed restriction maps can be found on DNA sequences and maps. The sites listed in these tables were identified by computer analysis of published sequences.

Where can I find a list of restriction enzymes?

For a list of many commonly used restriction enzymes, visit NEB. Restriction enzyme digestion is commonly used in molecular cloning techniques, such as PCR or restriction cloning. It is also used to quickly check the identity of a plasmid by diagnostic digest.

How accurate is a map of bacteriophage lambda cut sites?

A map of bacteriophage lambda was constructed, including accurate positions for all 41 cut sites made by 12 different restriction enzymes. Over 100 fragments from single, multiple, and partial enzyme digestions were measured versus standards that were calibrated with respect to DNA molecules of known sequence.