2011/08/01 by Geoffrey A. Lott, Alejandro Perdomo-Ortiz, Alejandro Perdomo‐Ortiz +5 · 133 citations
Biochemistry, Genetics and Molecular Biology · Chemistry · Neuroscience · Physics and Astronomy · #Absorption spectroscopy #Bilayer #Chemistry #Chromophore #Crystallography #Dimer #Exciton #Fluorescence #Fluorescence spectroscopy #Lipid bilayer #Liposome #Membrane #Optics #Organic chemistry #Photochemistry #Photoreceptor and optogenetics research #Photosynthetic Processes and Mechanisms #Physics #Porphyrin #Spectroscopy #Spectroscopy and Quantum Chemical Studies #Vesicle #physics.bio-ph #physics.chem-ph
paper · pdf · doi:10.1073/pnas.1017308108
published in Proceedings of the National Academy of Sciences 108(40), 16521-16526 (National Academy of Sciences) · Proc. Natl. Acad. Sci. (PNAS), 2011, in press
arxiv created 2011/08/01 · openalex publication_date 2011/09/22 · arxiv updated 2015/05/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
By applying a phase-modulation fluorescence approach to 2D electronic spectroscopy, we studied the conformation-dependent exciton coupling of a porphyrin dimer embedded in a phospholipid bilayer membrane. Our measurements specify the relative angle and separation between interacting electronic transition dipole moments and thus provide a detailed characterization of dimer conformation. Phase-modulation 2D fluorescence spectroscopy (PM-2D FS) produces 2D spectra with distinct optical features, similar to those obtained using 2D photon-echo spectroscopy. Specifically, we studied magnesium meso tetraphenylporphyrin dimers, which form in the amphiphilic regions of 1,2-distearoyl-sn-glycero-3-phosphocholine liposomes. Comparison between experimental and simulated spectra show that although a wide range of dimer conformations can be inferred by either the linear absorption spectrum or the 2D spectrum alone, consideration of both types of spectra constrain the possible structures to a "T-shaped" geometry. These experiments establish the PM-2D FS method as an effective approach to elucidate chromophore dimer conformation.