Chiu-Hao Chen

Publications (3)11.02 Total impact

• Article: Configuration of PKCalpha-C2 domain bound to mixed SOPC/SOPS lipid monolayers.

  Chiu-Hao Chen, Sárka Málková, Sai Venkatesh Pingali, Fei Long, Shekhar Garde, Wonhwa Cho, Mark L Schlossman
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  ABSTRACT: X-ray reflectivity measurements are used to determine the configuration of the C2 domain of protein kinase Calpha (PKCalpha-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 PKCalpha-C2 and a slab model representation of the lipid layer. The configuration of lipid-bound PKCalpha-C2 is described by two angles that define its orientation, theta = 35 degrees +/- 10 degrees and phi =210 degrees +/- 30 degrees, and a penetration depth (=7.5 +/- 2 A) into the lipid layer. In this structure, the beta-sheets of PKCalpha-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 PKCalpha-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 PKCalpha 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.
  Biophysical Journal 11/2009; 97(10):2794-802. · 3.65 Impact Factor
• Source

  Available from: pdx.edu

  Article: Structure and depletion at fluorocarbon and hydrocarbon/water liquid/liquid interfaces.

  Kaoru Kashimoto, Jaesung Yoon, Binyang Hou, Chiu-hao Chen, Binhua Lin, Makoto Aratono, Takanori Takiue, Mark L Schlossman
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  ABSTRACT: The results of x-ray reflectivity studies of two oil/water (liquid/liquid) interfaces are inconsistent with recent predictions of the presence of a vaporlike depletion region at hydrophobic/aqueous interfaces. One of the oils, perfluorohexane, is a fluorocarbon whose superhydrophobic interface with water provides a stringent test for the presence of a depletion layer. The other oil, heptane, is a hydrocarbon and, therefore, is more relevant to the study of biomolecular hydrophobicity. These results are consistent with the subangstrom proximity of water to soft hydrophobic materials.
  Physical Review Letters 09/2008; 101(7):076102. · 7.37 Impact Factor
• Source

  Available from: Jaesung Yoon

  Article: Structure and Depletion at Fluoro- and Hydro-carbon/Water Liquid/Liquid Interfaces

  Kaoru Kashimoto, Jaesung Yoon, Binyang Hou, Chiu-Hao Chen, Binhua Lin, Makoto Aratono, Takanori Takiue, Mark L Schlossman
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  ABSTRACT: The results of x-ray reflectivity studies of two oil/water (liquid/liquid) interfaces are inconsistent with recent predictions of the presence of a vapor-like depletion region at hydrophobic/aqueous interfaces. One of the oils, perfluorohexane, is a fluorocarbon whose super-hydrophobic interface with water provides a stringent test for the presence of a depletion layer. The other oil, heptane, is a hydrocarbon and, therefore, is more relevant to the study of biomolecular hydrophobicity. These results are consistent with the sub-angstrom proximity of water to soft hydrophobic materials. Comment: 28 pages, 9 figures, main text plus supplementary, to be published in Physical Review Letters
  07/2008;