THE COMPLEX LIES ON A CRYSTALLOGRAPHIC TWO-FOLD AXIS, AND ONLY ONE MONOMER-DNA HALF-SITE CONSTITUTES THE ASYMMETRIC UNIT. THE COORDINATES COMPRISE ONE REPRESSOR MONOMER AND ONE DNA STRAND FOR THE ENTIRE SITE. THE FULL COMPLEX CAN BE CONSTRUCTED BY GENERATING THE SECOND HALF USING THE CRYSTALLOGRAPHIC SYMMETRY OPERATION (X, -Y, -Z).
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要素
#1: DNA鎖
DNA (5'-D(*TP*AP*CP*GP*CP*AP*AP*AP*CP*GP*TP*TP*TP*GP*CP*GP*T )-3') / PURF OPERATOR
THE LEUCINE 54 LEVERS INTERDIGITATE FROM THE MINOR GROOVE SIDE BETWEEN THE CENTRAL C.G:G.C BASE ...THE LEUCINE 54 LEVERS INTERDIGITATE FROM THE MINOR GROOVE SIDE BETWEEN THE CENTRAL C.G:G.C BASE PAIR STEP OF PURF OPERATOR DNA. THE OPERATOR DNA IS THUS KINKED BY 50 DEGREES. SUBSTITUTING LEU 54 WITH MET YIELDS A MUTANT PURR THAT BINDS AND BENDS DNA SIMILARLY TO WILD TYPE. HOWEVER, THE ROUTES OF THE SIDE CHAINS AND THEIR CONTACTS TO THE C-G:G-C BASE PAIR STEP DIFFER.