A, binding ability of PKD domain and its mutants to
bovine-insoluble type I collagen fiber and elastin. B, purified EGFP
and fusion proteins of PKD and its three mutants. Various concentrations of
EGFP, and fusion proteins of PKD and its mutants were incubated with a fixed
amount of collagen (or elastin) in double distilled water at 40 °C for 1 h
with mixing. The free fluorescence intensity in the solution before and after
incubation was determined with spectrofluorometer. EGFP was used as the
control. The figure shows the equilibrium adsorption isotherms (B versus
F) by measuring the bounded protein amount (B) and the unbounded
protein amount (F). The data represent the mean of three experimental
repeats with S.D. ≤ 5%. ▪, PKD incubated with collagen; •, W34A
incubated with collagen; ▴, W36A incubated with collagen; ▾,
W34A/W36A incubated with collagen; ♦, EGFP incubated with collagen;
□, PKD incubated with elastin.