Imaging of monolayers composed of palmitic acid and lung surfactant protein B.
Near-field scanning optical microscopy and atomic force microscopy are used to probe the sub-micrometre phase structure in palmitic acid monolayers containing the 25 peptide amino terminus of lung surfactant protein B (SP-B(1-25)). Monolayers deposited onto mica substrates at a surface pressure of 15 mN m-1 exhibit a two-phase coexistence across a broad range of SP-B(1-25) concentrations. Monolayers containing 5 wt.% SP-B(1-25) or less exhibit an expanse of liquid condensed phase in which elliptical liquid expanded (LE) domains with areas of approximately 25 microm2 coexist. By contrast, monolayers containing 20 wt.% SP-B(1-25) exhibit an expanse of liquid expanded phase in which circular liquid condensed domains coexist. The phase distribution dependence on SP-B(1-25) concentration suggests that the peptide induces disorder in the monolayer.
Flanders
B N
BN
Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA.
Vickery
S A
SA
Dunn
R C
RC
D000595:Amino Acid Sequence; D008853:Microscopy / Q000379:methods; D018625:Microscopy, Atomic Force; D008969:Molecular Sequence Data; D019308:Palmitic Acid / Q000737:chemistry*; D011510:Proteolipids / Q000737:chemistry / Q000648:ultrastructure*; D011663:Pulmonary Surfactants / Q000737:chemistry / Q000648:ultrastructure*
D011510:Proteolipids; D011663:Pulmonary Surfactants; D019308:Palmitic Acid