| Mode of interaction of hydrophobic amphiphilic alpha-helical peptide/dipalmitoylphosphatidylcholine with phosphatidylglycerol or palmitic acid at the air-water interface. | |
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MedLine Citation:
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PMID: 16768510 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Surface pressure (pi)-, surface potential (DeltaV)-, dipole moment (mu( perpendicular))-area (A) isotherms and morphological behavior at the air-water interface were obtained for multicomponent monolayers of two different systems for dipalmitoylphosphatidylcholine (DPPC)/egg-phosphatidylglycerol (PG) (= 68:22, by weight)/Hel 13-5 and DPPC/palmitic acid (PA) (= 90:9, by weight)/Hel 13-5 (Hel 13-5 is a newly designed 18-mer amphiphilic alpha-helical peptide with 13 hydrophobic and 5 hydrophilic amino acid residues). The phase behavior of these model systems was investigated on a subsolution of 0.02 M tris(hydroxymethyl)aminomethane (Tris) buffer (pH 8.4) with 0.13 M NaCl at 298.2 K by employing the Wilhelmy method, the ionizing electrode method, and fluorescence microscopy. Especially, the present study focuses on the interfacial effect of the addition of Hel 13-5 on two binary systems, DPPC/egg-PG and DPPC/PA monolayers, as the substitute for pulmonary surfactant proteins, and on the respective roles of PG and PA for the monolayers in the three-component systems. Constant kink points ( approximately 42 mN m(-1)) clearly appear on the pi-A isotherms, independent of the compositions in the ternary systems, which corresponds to the Hel 13-5 collapse pressure similar to that of SP-B and SP-C as functions in multicomponent monolayers. This implies that Hel 13-5 is squeezed out of ternary monolayers above approximately 42 mN m(-1), resulting in two- to three-dimensional phase transformation. Furthermore, Langmuir isotherms clearly show that Hel 13-5 with egg-PG is squeezed out of the DPPC/egg-PG/Hel 13-5 system, whereas only Hel 13-5 is squeezed out of the DPPC/PA/Hel 13-5 system. Cyclic compression and expansion isotherms of these systems were carried out to confirm the spreading and respreading capacities. In addition, the interfacial behavior of the ternary mixtures has been analyzed by the additivity rule. Morphological examinations and comparisons have verified the interactions of Hel 13-5 with the representative miscible mixture (DPPC/PA system) by fluorescence microscopy. Consequently, distinct morphological variations corresponding to the squeeze-out behavior are observed as a fluorescent contrast recovery. Herein, a new mechanism of the refluorescent phenomenon is proposed by varying the surface composition of Hel 13-5. |
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Authors:
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Hiromichi Nakahara; Sannamu Lee; Gohsuke Sugihara; Osamu Shibata |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Langmuir : the ACS journal of surfaces and colloids Volume: 22 ISSN: 0743-7463 ISO Abbreviation: Langmuir Publication Date: 2006 Jun |
Date Detail:
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Created Date: 2006-06-13 Completed Date: 2007-07-20 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9882736 Medline TA: Langmuir Country: United States |
Other Details:
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Languages: eng Pagination: 5792-803 Citation Subset: IM |
Affiliation:
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Division of Biointerfacial Science, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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1,2-Dipalmitoylphosphatidylcholine
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chemistry* Air Amino Acid Sequence Hydrophobicity Macromolecular Substances / chemistry Microscopy, Fluorescence Models, Molecular Molecular Sequence Data Palmitic Acid / chemistry* Peptides / chemistry* Phosphatidylglycerols / chemistry* Protein Structure, Secondary Surface-Active Agents / chemistry Thermodynamics Water |
| Chemical | |
Reg. No./Substance:
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0/Macromolecular Substances; 0/Peptides; 0/Phosphatidylglycerols; 0/Surface-Active Agents; 2644-64-6/1,2-Dipalmitoylphosphatidylcholine; 57-10-3/Palmitic Acid; 7732-18-5/Water |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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