Kinetics of degradation of dipalmitoylphosphatidylcholine (DPPC) bilayers as a result of vipoxin phospholipase A2 activity: an atomic force microscopy (AFM) approach.
In this paper we used AFM as an analytical tool to visualize the degradation of a phospholipid bilayer undergoing hydrolysis of the vipoxin's PLA(2). We obtained time series images during the degradation process of supported 1, 2-dipalmitoylphosphatidylcholine (DPPC) bilayers and evaluated the occurrence and the growth rate of the bilayer defects. The special resolution of the AFM images allowed us to measure the area and the perimeter length of these defects and to draw conclusions about the kinetics of the enzyme reaction. Moreover, we also report for some unique characteristics discovered during the vipoxin's PLA(2) action. Experimentally for the first time, we observed the appearance and the growth of three-dimensional (3D), crystal-like structures within the formed defects of the degraded bilayer. In an effort to explain their nature, we applied bearing image analysis to estimate the volume of these crystals and we found that their growth rate follows a similar kinetic pattern as the degradation rate of the supported bilayer.
Sofia University, Faculty of Chemistry, Department of Physical Chemistry, Lab Biophysical Chemistry, 1, James Bourchier Avenue, Sofia 1164, Bulgaria. kbalashev@chem.uni-sofia.bg
Konstantin
K
Balashev
Vasil
V
Atanasov
Mariana
M
Mitewa
Svetla
S
Petrova
Thomas
T
Bjørnholm
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D001671:Biochemistry / Q000379:methods; D018360:Crystallography, X-Ray / Q000379:methods; D006868:Hydrolysis; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D018625:Microscopy, Atomic Force / Q000379:methods; D054467:Phospholipases A2 / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013997:Time Factors; D014757:Viper Venoms / Q000737:chemistry* / Q000378:metabolism
D008051:Lipid Bilayers; D008055:Lipids; D010743:Phospholipids; D014757:Viper Venoms; D015060:1,2-Dipalmitoylphosphatidylcholine; C033134:vipoxin; D054467:Phospholipases A2