Oligomerization analysis and hypothetical dimer configurations.
A, chromatograms of ALO from S200 size exclusion chromatography
coupled to differential pressure transducers and SLS and UV detectors.
Data lines show UV (solid), RALS (dot-dash), LALS
(dot-dot-dash), and DP (dotted). B, molecular
weight (MW) and intrinsic viscosity (IV) patterns of ALO.
Data lines show molecular weight (solid), LALS
(dot-dot-dash), and IV (dotted). The retention volume of ALO
(22.2 ml) is probably due to interactions with the column media. Using
standard proteins for calibration, such a retention volume corresponds to a
15-20-kDa protein (not shown). Hence, measurement of molecular mass by
SEC-SLS, which is independent from the retention volume on SEC, is appropriate
for ALO. C, sedimentation velocity analysis of ALO from analytical
ultracentrifugation at three different pH values: pH 5.5 (dashed), pH
7.0 (solid), and pH 8.0 (dotted). D, potential
dimer interactions. Crystallographic dimers are found in ALO and PFO (I)
crystals, and noncrystallographic dimers are seen in PFO (III) and ILY
crystals. Domains 1-3 are colored blue, and D4 is colored
orange.