title: Far-infrared spectroscopy of protein higher-order structures.
abstract: Far-infrared (FIR) spectroscopy in the spectral region of 50-450 cm(-1) was used to study a series of protein higher-order structures constructed using β-lactoglobulin and polyomavirus capsid protein VP1. There were marked differences in the spectra for β-lactoglobulin monomer and dimer and between untreated β-lactoglobulin and heat-induced gels formed at neutral pH. Untreated β-lactoglobulin and heat-induced gels formed at acidic pH exhibited little difference in their spectra. Assembly of the quaternary structure of polyomavirus virus-like particles also caused large changes in the FIR spectra. These findings suggest that FIR spectroscopy may prove useful in studying some protein quaternary and higher-order structures. There was evidence of detection of β-lactoglobulin dimerization, intermolecular disulfide bonding in heat-induced neutral gels, and polyomavirus virus-like particle assembly but no evidence that FIR could detect β-lactoglobulin fibrils with their polymeric structure and hydrogen-bonded intermolecular β-pleated sheeting.
authors.affiliation: The University of Queensland, NCRIS Biotechnology Products, Australian Institute for Bioengineering and Nanotechnology, Brisbane QLD 4072, Australia. r.falconer@uq.edu.au
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Falconer
authors.forename: Hidayatul A
authors.initials: HA
authors.lastname: Zakaria
authors.forename: Yuan Y
authors.initials: YY
authors.lastname: Fan
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Bradley
authors.forename: Anton P J
authors.initials: AP
authors.lastname: Middelberg
mesh_terms: D000818:Animals; D036022:Capsid Proteins / Q000737:chemistry / Q000378:metabolism; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D007782:Lactoglobulins / Q000737:chemistry / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D011487:Protein Conformation; D055503:Protein Multimerization; D055550:Protein Stability; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D013055:Spectrophotometry, Infrared / Q000379:methods*; D013696:Temperature; D014771:Virion / Q000737:chemistry / Q000378:metabolism
chemical_list: D036022:Capsid Proteins; D007782:Lactoglobulins; D011506:Proteins; C062481:VP1 protein, polyomavirus