the effect of a cationic detergent , lauryl pyridiniumchloride ( lpc ) , and an anionic one , sodium n-octylbenzenesulfonate ( sobs ) , on the conformation of unfractionated escherichia coli trna was investigated at various molar ratios of detergent to trna ( d/r ) in the presence and absence of mg2+ and na+ ions by measuring the circular dichroism ( cd ) at 265 nm and 340 nm , which reflects conformational change involving base pairs and/or base stacking , and the disymmetry in the vicinity of 4-thiouridylate ( 4-tu ) , respectively .
C0003075
anionic
C0022023
ions