K. Yase et T. Udaka, 2-DIMENSIONAL CRYSTALLIZATION OF FERRITIN MOLECULES AT THE AIR-WATER-INTERFACE, Journal of crystal growth, 166(1-4), 1996, pp. 946-951
Three kinds of dialkyl compounds, dimethyl-dioctadecyl-ammonium bromid
e, sodium dioctadecyl-phosphate, and sodium dioctadecanoyl-sulphate, a
re employed as monolayers adsorbing ferritin proteins at the air-water
interface. After incubating the lipid monolayer on the water surface,
proteins are injected into the subphase. After an elapsed time of bet
ween 10 and 50 min, the lipid-ferritin complexes are horizontally tran
sferred onto a carbon film and observed by transmission electron micro
scope. Although the dialkyl-ammonium salt has a smaller adsorption rat
e of proteins (3.2 x 10(9) molecules cm(-2) min(-1)) than those of pho
sphate and sulphate (7.7 x 10(9) and 8.6 x 10(9) molecules cm(-2) min(
-1), respectively), ammonium salt has the tendency to yield the best t
wo-dimensional crystals of protein, and constructs small crystals cons
isting of 10-100 proteins in a short incubation time, For the first ti
me, it was confirmed from quantitative analysis that two-dimensional c
rystal growth of proteins would require both the adsorbing ability and
fluidity of the lipid monolayer.