Introduction

Brief description of system

EcoR124I is a Type I restriction modification system. It is a protein complex made up of a core Methyltransferase (MTase) consisting of 1 HsdS (Specificity) subunit and 2 HsdM (Methylase) subunits. A first then a second HsdR subunit bind to the MTase to form a restriction deficient R1-complex and then a restriction-proficient Endonuclease (ENase) complex

     

Type I R-M enzymes, as either a R1 or R2 complex, translocate the DNA in the presence of ATP and Mg2+. EcoKI is the most studied Type I R-M system and all models have until now been based upon this enzyme.  In the first 3 months of my studies data has been collected which is beginning to show significant differences between EcoKI and EcoR124I.  The primary difference noted so far is the dimerisation undertaken by the EcoKI system prior to translocation and cleavage

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