Low frequency (collective) modes in proteins (~10-600 cm-1) have received considerable attention because it is thought that domains or sub-domains in proteins are involved in correlated motions on picosecond timescales. It is clear that motions at these frequencies make an important contribution to the mean-square displacement of atoms from their equilibrium (vibrational) positions. Thus, these motions are the first steps in functionally important motions leading to large-scale conformational changes. Such changes are critical to structural and functional processes like protein folding, cooperativity, and protein-protein or protein-ligand interactions involved in electron transfer, enzyme catalysis, and signaling. Poly-amino acids provide a model system for understanding collective modes in proteins. By polymerizing different amino acid monomers, varying secondary and tertiary structures can be created and studied with far infrared absorption spectroscopy. They provide a controlled method for identifying and characterizing any ?breathing modes? attributable to various ?-helical or ?-sheet type structures in proteins. We have also obtained the far-infrared spectra of poly-L-phenylalanine, poly-L-alanine, poly-L-tryptophan, and poly-L-leucine from 10 to 295 K in 20 K increments. The results demonstrate (1) there are several (ranging from 4-10, depending on the poly-amino acid) low frequency modes in the far-infrared region, (2) the bands below ~200 cm-1 all increase in frequency with decreasing temperature, and (3) this temperature-dependence increases with decreasing band frequency. These results suggest that these modes are Hhighly anharmonic, consistent with various computational studies. Currently, curve-fitting analysis is being used to aid in the identification of various modes, assignment of their origins, and their sensitivity to temperature.

National Institute of Health (NIH)
National Center for Research Resources (NCRR)
Biotechnology Resource Grants (P41)
Project #
Application #
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Albert Einstein College of Medicine
United States
Zip Code
Vongsvivut, Jitraporn; Fernandez, Jason; Ekgasit, Sanong et al. (2004) Characterization of supported cylinder-planar germanium waveguide sensors with synchrotron infrared radiation. Appl Spectrosc 58:143-51
Masip, Lluis; Pan, Jonathan L; Haldar, Suranjana et al. (2004) An engineered pathway for the formation of protein disulfide bonds. Science 303:1185-9
Huang, Raymond Y; Miller, Lisa M; Carlson, Cathy S et al. (2003) In situ chemistry of osteoporosis revealed by synchrotron infrared microspectroscopy. Bone 33:514-21
Rashidzadeh, Hassan; Khrapunov, Sergei; Chance, Mark R et al. (2003) Solution structure and interdomain interactions of the Saccharomyces cerevisiae ""TATA binding protein"" (TBP) probed by radiolytic protein footprinting. Biochemistry 42:3655-65
Uchida, Takeshi; Takamoto, Keiji; He, Qin et al. (2003) Multiple monovalent ion-dependent pathways for the folding of the L-21 Tetrahymena thermophila ribozyme. J Mol Biol 328:463-78
Taylor, Colleen M; Watton, Stephen P; Bryngelson, Peter A et al. (2003) Inner-sphere complexation of cobalt(II) 2,9-dimethyl-1,10-phenanthroline ([Co(neo)]2+) with commercial and sol-gel derived silica gel surfaces. Inorg Chem 42:312-20
Dhavan, Gauri M; Crothers, Donald M; Chance, Mark R et al. (2002) Concerted binding and bending of DNA by Escherichia coli integration host factor. J Mol Biol 315:1027-37
Uchida, Takeshi; He, Qin; Ralston, Corie Y et al. (2002) Linkage of monovalent and divalent ion binding in the folding of the P4-P6 domain of the Tetrahymena ribozyme. Biochemistry 41:5799-806
Tang, Qun; Carrington, Paul E; Horng, Yih-Chern et al. (2002) X-ray absorption and resonance Raman studies of methyl-coenzyme M reductase indicating that ligand exchange and macrocycle reduction accompany reductive activation. J Am Chem Soc 124:13242-56
Guan, Jing-Qu; Vorobiev, Sergeui; Almo, Steven C et al. (2002) Mapping the G-actin binding surface of cofilin using synchrotron protein footprinting. Biochemistry 41:5765-75

Showing the most recent 10 out of 68 publications