title: THz time domain spectroscopy of biomolecular conformational modes.
abstract: We discuss the use of terahertz time domain spectroscopy for studies of conformational flexibility and conformational change in biomolecules. Protein structural dynamics are vital to biological function with protein flexibility affecting enzymatic reaction rates and sensory transduction cycling times. Conformational mode dynamics occur on the picosecond timescale and with the collective vibrational modes associated with these large scale structural motions in the 1-100 cm(-1) range. We have performed THz time domain spectroscopy (TTDS) of several biomolecular systems to explore the sensitivity of TTDS to distinguish different molecular species, different mutations within a single species and different conformations of a given biomolecule. We compare the measured absorbances to normal mode calculations and find that the TTDS absorbance reflects the density of normal modes determined by molecular mechanics calculations, and is sensitive to both conformation and mutation. These early studies demonstrate some of the advantages and limitations of using TTDS for the study of biomolecules.
authors.affiliation: Physics Department, University at Buffalo, Buffalo, NY, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Markelz
authors.forename: Scott
authors.initials: S
authors.lastname: Whitmire
authors.forename: Jay
authors.initials: J
authors.lastname: Hillebrecht
authors.forename: Robert
authors.initials: R
authors.lastname: Birge
mesh_terms: D000818:Animals; D001436:Bacteriorhodopsins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics; D003461:Crystallography / Q000295:instrumentation / Q000379:methods*; D019617:Halobacterium salinarum / Q000737:chemistry / Q000145:classification; D046911:Macromolecular Substances; D008872:Microwaves; D009113:Muramidase / Q000032:analysis / Q000737:chemistry*; D009206:Myocardium / Q000737:chemistry; D009211:Myoglobin / Q000032:analysis / Q000737:chemistry*; D055095:Optics and Photonics / Q000295:instrumentation; D010775:Photic Stimulation; D011487:Protein Conformation; D011506:Proteins / Q000032:analysis / Q000737:chemistry; D012680:Sensitivity and Specificity; D013045:Species Specificity; D013057:Spectrum Analysis / Q000295:instrumentation / Q000379:methods*; D013696:Temperature
chemical_list: D046911:Macromolecular Substances; D009211:Myoglobin; D011506:Proteins; D001436:Bacteriorhodopsins; D009113:Muramidase