Physical and chemical characterization of the oligomerization state of the Aeromonas hydrophila lipase/acyltransferase
Aeromonas glycerophospholipid:cholesterol acyl transferase undergoes a conformational transition upon activation by treatment with trypsin. Chemical cross-linking and sedimentation velocity analysis showed that the lipase dimerizes due to removal of a region near its C-terminus. The lipase monomer has a sedimentation coefficient s20.w = 2.83 S, whereas the dimer has s20.w = 3.65 +/- 0.22 S. Hydrodynamic analysis using these sedimentation values and the masses determined by mass spectrometry indicated that the monomers are aligned side-by-side in the dimer. An important change occurs in the apparent partial specific volume of the molecule upon activation.
Keywords: Acyltransferases/*chemistry/isolation & purification ; Aeromonas hydrophila/*enzymology ; Cross-Linking Reagents ; Dimethyl Suberimidate ; Electrophoresis ; Polyacrylamide Gel ; Lipase/*chemistry/isolation & purification ; Macromolecular Substances ; Mass Spectrometry ; Molecular Weight ; Ultracentrifugation
Department of Biochemistry and Microbiology, University of Victoria, BC, Canada.
Record created on 2009-01-30, modified on 2016-08-08