Configuration of PKCalpha-C2 Domain Bound to Mixed SOPC/SOPS Lipid Monolayers

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Biophysical Journal

DOI:https://doi.org/10.1016/j.bpj.2009.08.037· OSTI ID:1019655

Chen, C; Malkova, S; Venkatesh Pingali, S; Long, F; Garde, S; Cho, W; Schlossman, M

X-ray reflectivity measurements are used to determine the configuration of the C2 domain of protein kinase C{alpha} (PKC{alpha}-C2) bound to a lipid monolayer of a 7:3 mixture of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1-stearoyl-2-oleoyl-sn-glycero-3-phosphoserine supported on a buffered aqueous solution. The reflectivity is analyzed in terms of the known crystallographic structure of PKC{alpha}-C2 and a slab model representation of the lipid layer. The configuration of lipid-bound PKC{alpha}-C2 is described by two angles that define its orientation, {theta} = 35{sup o} {+-} 10{sup o} and {phi} = 210{sup o} {+-} 30{sup o}, and a penetration depth (=7.5 {+-} 2 {angstrom}) into the lipid layer. In this structure, the {beta}-sheets of PKC{alpha}-C2 are nearly perpendicular to the lipid layer and the domain penetrates into the headgroup region of the lipid layer, but not into the tailgroup region. This configuration of PKC{alpha}-C2 determined by our x-ray reflectivity is consistent with many previous findings, particularly mutational studies, and also provides what we believe is new molecular insight into the mechanism of PKC{alpha} enzyme activation. Our analysis method, which allows us to test all possible protein orientations, shows that our data cannot be explained by a protein that is orientated parallel to the membrane, as suggested by earlier work.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1019655
• Report Number(s): BNL--95501-2011-JA
• Journal Information: Biophysical Journal, Journal Name: Biophysical Journal Journal Issue: 10 Vol. 97; ISSN 0006-3495; ISSN BIOJAU
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
99 GENERAL AND MISCELLANEOUS
AQUEOUS SOLUTIONS
CONFIGURATION
ENZYMES
LIPIDS
MIXTURES
ORIENTATION
PENETRATION DEPTH
PHOSPHOTRANSFERASES
PROTEINS
REFLECTIVITY
national synchrotron light source