The adsorbed conformation of globular proteins at the air/water interface

Lad, M.D., Birembaut, F., Matthew, J.M., Frazier, R. ORCID: https://orcid.org/0000-0003-4313-0019 and Green, R. J. (2006) The adsorbed conformation of globular proteins at the air/water interface. Physical Chemistry Chemical Physics, 8 (18). pp. 2179-2186. ISSN 1463-9076 doi: 10.1039/b515934b

Abstract/Summary

External reflection FTIR spectroscopy and surface pressure measurements were used to compare conformational changes in the adsorbed structures of three globular proteins at the air/water interface. Of the three proteins studied, lysozyme, bovine serum albumin and P-lactoglobulin, lysozyme was unique in its behaviour. Lysozyme adsorption was slow, taking approximately 2.5 h to reach a surface pressure plateau (from a 0.07 mM solution), and led to significant structural change. The FTIR spectra revealed that lysozyme formed a highly networked adsorbed layer of unfolded protein with high antiparallel beta-sheet content and that these changes occurred rapidly (within 10 min). This non-native secondary structure is analogous to that of a 3D heat-set protein gel, suggesting that the adsorbed protein formed a highly networked interfacial layer. Albumin and P-lactoglobulin adsorbed rapidly (reaching a plateau within 10 min) and with little chance to their native secondary structure.