The adsorbed conformation of globular proteins at the air/water interface.
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 beta-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 beta-lactoglobulin adsorbed rapidly (reaching a plateau within 10 min) and with little change to their native secondary structure.
Lad
Mitaben D
MD
School of Chemistry, The University of Reading, PO Box 224, Whiteknights, Reading, UK RG6 6AD.
Birembaut
Fabrice
F
Matthew
Joanna M
JM
Frazier
Richard A
RA
Green
Rebecca J
RJ
D000327:Adsorption; D000388:Air; D007700:Kinetics; D007782:Lactoglobulins / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
D007782:Lactoglobulins; D014867:Water; D012710:Serum Albumin, Bovine; D009113:Muramidase