Abstract

The determination of ultrafast anisotropy changes can be of great value in determining how energy flows between different cofactors in an assembly. The techniques of anisotropy measurement have been significantly refined in order that coherent and orientational aspects of energy transfer can be determined with high accuracy. Femtosecond transient dynamics within the dimeric subunit of a bacterial light-harvesting complex have been investigated using magic angle and polarized pump-probe spectroscopy. Oscillations of 170 cm-1 and ~ 20 cm-1, 50 cm-1 and 115 cm-1 are observed in the isotropic signal and ~ 500 cm-1 in the anisotropy. The Stokes shift and dephasing of the dimer exciton levels occurs on a sub-50 fs timescale. The re-assembled aggregate exhibits ultrafast spectral evolution and biphasic anisotropy decay. Collectively, the results support a view of energy migration within LH-1 complexes as proceeding by strongly scattered excitation transfer between states of the dimeric subunits.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR001348-20
Application #
6480853
Study Section
Project Start
2001-08-01
Project End
2002-07-31
Budget Start
1997-10-01
Budget End
1998-09-30
Support Year
20
Fiscal Year
2001
Total Cost
$155,764
Indirect Cost

  Institution

Name
University of Pennsylvania
Department
Type
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104

  Publications

Sheth, Rahul A; Arellano, Ronald S; Uppot, Raul N et al. (2015) Prospective trial with optical molecular imaging for percutaneous interventions in focal hepatic lesions. Radiology 274:917-26
Roussakis, Emmanuel; Spencer, Joel A; Lin, Charles P et al. (2014) Two-photon antenna-core oxygen probe with enhanced performance. Anal Chem 86:5937-45
Courter, Joel R; Abdo, Mohannad; Brown, Stephen P et al. (2014) The design and synthesis of alanine-rich ?-helical peptides constrained by an S,S-tetrazine photochemical trigger: a fragment union approach. J Org Chem 79:759-68
Kuroda, Daniel G; Bauman, Joseph D; Challa, J Reddy et al. (2013) Snapshot of the equilibrium dynamics of a drug bound to HIV-1 reverse transcriptase. Nat Chem 5:174-81
Lam, A R; Moran, S D; Preketes, N K et al. (2013) Study of the ?D-crystallin protein using two-dimensional infrared (2DIR) spectroscopy: experiment and simulation. J Phys Chem B 117:15436-43
Kuroda, Daniel G; Singh, Prabhat K; Hochstrasser, Robin M (2013) Differential hydration of tricyanomethanide observed by time resolved vibrational spectroscopy. J Phys Chem B 117:4354-64
Singh, Prabhat K; Kuroda, Daniel G; Hochstrasser, Robin M (2013) An ion's perspective on the molecular motions of nanoconfined water: a two-dimensional infrared spectroscopy study. J Phys Chem B 117:9775-84
Chuntonov, Lev; Ma, Jianqiang (2013) Quantum process tomography quantifies coherence transfer dynamics in vibrational exciton. J Phys Chem B 117:13631-8
Culik, Robert M; Annavarapu, Srinivas; Nanda, Vikas et al. (2013) Using D-Amino Acids to Delineate the Mechanism of Protein Folding: Application to Trp-cage. Chem Phys 422:
Goldberg, Jacob M; Speight, Lee C; Fegley, Mark W et al. (2012) Minimalist probes for studying protein dynamics: thioamide quenching of selectively excitable fluorescent amino acids. J Am Chem Soc 134:6088-91

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