Conformational changes in SP-B as a function of surface pressure

Wilfred K. Fullagar, Karen A. Aberdeen, David G. Bucknall, Paulus A. Kroon, Ian R. Gentle

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

X-ray reflectivity of bovine and sheep surfactant-associated protein B (SP-B) monolayers is used in conjunction with pressure-area isotherms and protein models to suggest that the protein undergoes changes in its tertiary structure at the air/water interface under the influence of surface pressure, indicating the likely importance of such changes to the phenomena of protein squeeze out as well as lipid exchange between the air-water interface and subphase structures. We describe an algorithm based on the well-established box- or layer-models that greatly assists the fitting of such unknown scattering-length density profiles, and which takes the available instrumental resolution into account. Scattering-length density profiles from neutron reflectivity of bovine SP-B monolayers on aqueous subphases are shown to be consistent with the exchange of a large number of labile protons as well as the inclusion of a significant amount of water, which is partly squeezed out of the protein monolayer at elevated surface pressures.

Original languageEnglish
Pages (from-to)2624-2632
Number of pages9
JournalBiophysical Journal
Volume85
Issue number4
DOIs
Publication statusPublished - 1 Oct 2003

ASJC Scopus subject areas

  • Biophysics

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