Endonucleases are enyzmes (usually derived from bacterial sources) which cleave DNA at defined "restriction" sites.

learn more… | top users | synonyms

0
votes
0answers
3 views

Molecular Cloning- Blunt end restriction endonucleases

I work in a microbiology lab where we do a lot of cloning. I have always used restriction endonucleases to cleave the DNA to have sticky ends and not blunt ends. I currently am working on a project ...
4
votes
3answers
52 views

How many Type II restrictions enzymes are currently available (commercially) [closed]

How many Type II restrictions enzymes are currently available (commercially) for purchase as of the date of this posting (September 1, 2014)
1
vote
1answer
30 views

How do Type I restriction enzymes work?

According to NCBI, type I REases have a specific target sequence but randomly make cuts at sites far from the target sequence. How does the restriction enzyme travel from the target sequence to the ...
3
votes
1answer
180 views

What does 'H' in BamHI stand for?

It's not explained on the wikipedia page. So if, apparently, 'H' is not relevant, why is it part of the name? And if it is relevant, why is it not explained?
2
votes
1answer
55 views

How was Restriction Site of EcoRI sequenced?

The sequence of restriction site of EcoRI - GAATTC was identified in the early 1970s, before Sanger Sequencing was invented.(1977) How was the restriction site of EcoRI sequenced ?
3
votes
3answers
103 views

Restriction endonucleases are found in?

Quoting from : Scientific American July 1975 The Manipulation of genes by Stanley Cohen : Restriction endonucleases (and modification methylases) are widespread in microorganisms; genes for ...
1
vote
2answers
54 views

Removing a restriction site and introducing other at its place

What would you do if you want to remove an EcoRI restriction site and introduce BamHI restriction site at apprx. the same location ? One of the answers in my textbook was : To construct a DNA ...
1
vote
0answers
45 views

DNA fingerprinting

I would like to make my own DNA fingerprint - just for fun to have my "autoportrait":). I was looking around a bit and all the commercial kits you can have are very expensive. Can you suggest me a ...
2
votes
2answers
2k views

Why restriction enzymes cut (usually) at palindromic sequences?

Restriction enzymes usually cut only at palindromic sequences. Is there any specific reason for that ? Is there any advantage for bacteria if it cuts up virus at this type of sequences ?
2
votes
2answers
430 views

What can cause incompatible sticky ends to be ligated?

Actual question I have reason to believe (details see below) that in a ligation I carried out, an EcoRI sticky end (EcoRI: G'AATT_C) and an XmaI sticky end (XmaI: C'CCGG_G) were somehow ligated ...
1
vote
2answers
305 views

Gel electrophoresis question

Leena is a molecular biology student. She purifies two fragments of DNA, 800 and 300 base pairs long. These were obtained from a plasmid after digesting it with HindIII. Each of these fragments has a ...
5
votes
4answers
418 views

What is the advantage of restriction enzymes cutting only at specific sites?

Bacteriophages have sequences which often do not have specific sites for restriction enzymes of bacteria to cut at and so can attack the bacteria. Wouldn't it be better if bacteria had something ...
1
vote
1answer
576 views

How effective are restriction enzymes in protecting bacteria?

Bacteria use restriction enzymes to cut DNA of bacteriophages. Virus mutates really fast. Won't a point mutation in restriction site render the restriction enzymes of the bacteria useless ? So how ...
5
votes
2answers
174 views

What are common causes of unexpected ligation products?

I digested two plasmids, one with EcoRI and AgeI and the other with EcoRI and XmaI. Digests looked as expected, so I purified the respective fragments and set up the T4 DNA ligation (AgeI and XmaI ...
1
vote
1answer
109 views

Can viruses protect themselves against restriction enzymes?

Restriction enzymes cut the DNA of bacteriophages. Have bacteriophages evolved any mechanism to protect themselves from it ?
2
votes
2answers
606 views

How prevalent is Taq polymerase in adding 3' A overhangs to the PCR product?

I am conducting a mutagenesis on a gene in vivo of which I need to ligate into an expression vector. The primers I have designed overlap restriction sites of which I plan to use to ligate into the ...
1
vote
2answers
2k views

Restriction Mapping of Plasmid Assignment

pUWL22 is a circular, double stranded, 10.5 kb plasmid. It contains a gene encoding an enzyme that confers ampicillin resistance in the host bacterium. Cloning into the kpn I and Sst I sites ...
5
votes
2answers
2k views

Primer design for introduction of restriction sites flanking a gene of interest

I am wondering what the correct method for primer design to introduce restriction sites. Specifically between two methods. 1) Primer first partially hybridises to the gene, has a mis-match where the ...
12
votes
3answers
724 views

Why do restriction enzymes tend to have an even number of bases in their recognition site?

When reading my textbook I noticed that in all examples but one from eight the recognition site was an even number of bases. I wondered if this was just a co-incidence, so I took the data from this ...