Restriction enzyme: Difference between revisions
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Restriction [[Endonucleases|Endonucleases]] cut [[DNA|DNA]] at a specific sequence, normally 4, 6 or 8 bases long. They recognise specific [[ | Restriction [[Endonucleases|Endonucleases]] cut [[DNA|DNA]] at a specific sequence, normally 4, 6 or 8 bases long. They recognise specific [[Palindromic base sequences|palindromic base sequences]] in [[DNA|DNA]] and are used to selectively cut DNA into defined fragments at sites known as '[[Restriction site|restriction sites]]'. Different restriction nucleases are obtained and purified from different species of bacteria. These [[Enzymes|enzymes]] are made in [[Bacteria|bacteria]] to degrade viral DNA. Cutting [[DNA]] with restriction enzymes can produce fragments with either [[Blunt ends|blunt]] or [[‘sticky’ ends|sticky ends]]. Different restriction enzymes recognise different DNA sequences.<br> | ||
Examples of restriction endonucleases are: | Examples of restriction endonucleases are: | ||
*[[EcoRI|''Eco''RI]]- recognines the sequence GAATTC | *[[EcoRI|''Eco''RI]]- recognines the sequence GAATTC | ||
*[[BamHI|''Bam''HI]]- recognises the sequence GGATCC | *[[BamHI|''Bam''HI]]- recognises the sequence GGATCC | ||
*[[HaeIII|''Hae''III]]- recognises GGCC | *[[HaeIII|''Hae''III]]- recognises GGCC | ||
Both ''Eco''RI and ''Bam''HI produce fragments with [[ | Both ''Eco''RI and ''Bam''HI produce fragments with [[‘sticky’ ends|staggered ends]], whilst ''Hae''III produces a DNA fragment with [[Blunt ends|blunt ends]] i.e. there is no overhang. | ||
Also see [[Restriction endonucleases|Restriction endonucleases]] | |||
Revision as of 21:28, 22 October 2012
Restriction Endonucleases cut DNA at a specific sequence, normally 4, 6 or 8 bases long. They recognise specific palindromic base sequences in DNA and are used to selectively cut DNA into defined fragments at sites known as 'restriction sites'. Different restriction nucleases are obtained and purified from different species of bacteria. These enzymes are made in bacteria to degrade viral DNA. Cutting DNA with restriction enzymes can produce fragments with either blunt or sticky ends. Different restriction enzymes recognise different DNA sequences.
Examples of restriction endonucleases are:
Both EcoRI and BamHI produce fragments with staggered ends, whilst HaeIII produces a DNA fragment with blunt ends i.e. there is no overhang.
Also see Restriction endonucleases