movement and requirements of type I restriction endonuclease

type I restriction endonucleases move along DNA in reaction and require Mg++, SAM (S-adenosyl methionine) and ATP as co-factor.

type I restriction endonuclease

Type I restriction endonucleases consist of three different subunits: 1. restrictive subunit which cut the DNA 2. modification subunit 3. specificity subunit which specifies the recognition site. These enzymes recognize the restriction site but they do not cut at the cleavage site or restriction site. These enzymes cut the DNA within the 1000bp away from recognition site or restriction site.

type I restriction endonuclease

Type I restriction endonucleases consist of three different subunits: 1. restrictive subunit which cut the DNA 2. modification subunit 3. specificity subunit which specifies the recognition site. These enzymes recognize the restriction site but they do not cut at the cleavage site or restriction site. These enzymes cut the DNA within the 15bp long sequence from recognition site or restriction site.

types of restriction endonucleases

there are three types of restriction endonucleases Type I Type II Type III Type II restriction endonucleases are the most preferable enzymes to cut the DNA in rDNA technology because of its specificity

Star activity of restriction endonuclease

restriction endonuclease cut at different position in the same sequence (restriction site).

vector must contain

1. ori region - origin of replication according to host. 2. selectable markers genes such ampicillin resistant gene, kanamycin resistant gene or tetracyclin resistant gene etc. 3. there should be MCS ( multiple cloning site) 4. there should be specific control systems such as promoter, terminator and RBS (ribosome binding site) etc

Role of SDS

SDS is a detergent. it can be use to rupture the cell wall and to degrade(breakdown in small fragments or mono units) the protein