K. Moriyama et al., Conformational changes of lysozymes with different numbers of disulfide bridges in sodium dodecyl sulfate solutions, COLLOID P S, 278(10), 2000, pp. 979-985
Four disulfide bridges of hen egg-white lysozyme were selectively reduced t
o obtain its derivatives with three, two, and zero disulfide bridges (desig
nated as 3SS, 2SS, and 0SS lysozymes, respectively). The 3SS lysozyme maint
ained the native conformation at pH 7.0 and 3.0. Even upon the reduction of
two disulfide bridges, the protein conformation still remained unchanged a
t pH 7.0. Upon the reduction of all four disulfide bridges, the helicity, [
theta](270), and tryptophan fluorescence changed at pH 3.0 as well as at pH
7.0. The helicity of each derivative increased in a solution of sodium dod
ecyl sulfate (SDS). The SDS-induced helicity of the 0SS lysozyme was lower
at pH 7.0 and higher at pH 3.0 than that of the intact lysozyme with four d
isulfide bridges. The helix formation appears to occur in originally nonhel
ical parts in each derivative at pH 7.0. In the cases of the 2SS and 0SS ly
sozymes at pH 3.0, however, some of the helices appear to be reformed also
at moieties where the original helices are disrupted upon the cleavage of d
isulfide bridges.