Denaturation resistance of beta-lactoglobulin in monomolecular films at the air-water interface.
Using X-ray reflectometry we report strong differences in the denaturation response of beta-lactoglobulin adsorbed as a monomolecular film at the air-water interface from that observed in mixed denaturant/beta-lactoglobulin bulk solutions. Using the "flow trough" technique an isolated monomolecular film of the protein showed little change in structure when subjected to a 4.0 M guanidinium hydrochloride substrate. Unlike the bulk solution where a new protein layer structure appears, small changes in the protein packing and the roughness of the film are the only evidence of change. These parameters have been studied as a function of denaturant concentration and film quality. The strength of the response depends on the degree of perfection of the originally formed film; quickly formed films are more easily denatured. As the response is so subtle, possible interfering effects such as denaturant release of protein adsorbed on the trough have been quantified.
Lin
Jhih-Min
JM
Research School of Chemistry, The Australian National University, Canberra ACT 0200, Australia.
White
John W
JW
D000388:Air; D019791:Guanidine / Q000737:chemistry; D007782:Lactoglobulins / Q000737:chemistry*; D011489:Protein Denaturation; D014867:Water / Q000737:chemistry*
D007782:Lactoglobulins; D014867:Water; D019791:Guanidine