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From 2006.igem.org
Recombinase Enhancer R.C. Johnson and M.F. Bruist. 1989. Intermediates in Hin-mediated DNA inversion: a role for Fis and the recombinational enhancer in the strand exchange reaction [1] -RE sequence must be present -w/o RE, Hin can still assemble to with the two Hix’s however, Hin can’t generate inversion -Prevention of Fis binding causes loss of enhancer function -60 bp in length -Binds two Fis proteins (98 AA’s) -Enhancer cannot function when located too close to a recombination site -HU facilitates the required bending of the DNA to create the inversion interaction -HU stimulation is dependent upon location of RE -Dependence upon HU is lesser when distance between RE and recombination site is greater -Required to induce the bending of the shorter, yet stiffer, segment of DNA -When RE is located >650 bp for the recombination site the dependence upon HU to form the complex is lost -RE combined w/ supercoiling mediate the rotation of DNA strands subsequent to double-stranded cleavage by Hin within two recombination sites
Haykinson and Johnson. 1993. DNA looping and the helical repeat in vitro and in vivo: effect of HU protein and enhancer location on Hin invertasome assembly [2] -The two recombination sites bound by Hin are assembled together at the Fis-bound RE -w/o HU invertasome assembly is very inefficient -“HU is the only protein in E. coli that can promote invertasome formation with short DNA lengths between RE and recombination sites -HU binds non-specifically to DNA between the enhancer and recombination site to facilitate DNA looping -“The RE can function at great distances !!! >4 kb !!! and on either side of a recombination site on a plasmid to stimulate Hin-mediated DNA inversion” -RE is not functional at a position 32 bp minimum -Due to restricted looping
