Anisotropic energy flow and allosteric ligand binding in albumin.
Allosteric interactions in proteins generally involve propagation of local structural changes through the protein to a remote site. Anisotropic energy transport is thought to couple the remote sites, but the nature of this process is poorly understood. Here, we report the relationship between energy flow through the structure of bovine serum albumin and allosteric interactions between remote ligand binding sites of the protein. Ultrafast infrared spectroscopy is used to probe the flow of energy through the protein backbone following excitation of a heater dye, a metalloporphyrin or malachite green, bound to different binding sites in the protein. We observe ballistic and anisotropic energy flow through the protein structure following input of thermal energy into the flexible ligand binding sites, without local heating of the rigid helix bundles that connect these sites. This efficient energy transport mechanism enables the allosteric propagation of binding energy through the connecting helix structures.
Department of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia 30322, USA.
Guifeng
G
Li
Department of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia 30322, USA.
Donny
D
Magana
Department of Chemistry, Emory University, 1515 Dickey Dr, Atlanta, Georgia 30322, USA.
R Brian
RB
Dyer
D000495:Allosteric Site; D000818:Animals; D016880:Anisotropy; D002417:Cattle; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D008665:Metalloporphyrins / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
D004396:Coloring Agents; D008024:Ligands; D008665:Metalloporphyrins; D012710:Serum Albumin, Bovine