Hydrophobic organization of membrane proteins.
Membrane-exposed residues are more hydrophobic than buried interior residues in the transmembrane regions of the photosynthetic reaction center from Rhodobacter sphaeroides. This hydrophobic organization is opposite to that of water-soluble proteins. The relative polarities of interior and surface residues of membrane and water soluble proteins are not simply reversed, however. The hydrophobicities of interior residues of both membrane and water-soluble proteins are comparable, whereas the bilayer-exposed residues of membrane proteins are more hydrophobic than the interior residues, and the aqueous-exposed residues of water-soluble proteins are more hydrophilic than the interior residues. A method of sequence analysis is described, based on the periodicity of residue replacement in homologous sequences, that extends conclusions derived from the known atomic structure of the reaction center to the more extensive database of putative transmembrane helical sequences.
Rees
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Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.
DeAntonio
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Eisenberg
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D001426:Bacterial Proteins; D002462:Cell Membrane / Q000032:analysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005583:Fourier Analysis; D008565:Membrane Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D011487:Protein Conformation; D012242:Rhodobacter sphaeroides / Q000648:ultrastructure*; D012995:Solubility; D014867:Water
D001426:Bacterial Proteins; D008565:Membrane Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D014867:Water