Ultrafast coherent motion and helix rearrangement of homodimeric hemoglobin visualized with femtosecond X-ray solution scattering

• Published in: Nature communications Vol. 12; no. 1; p. 3677
• Main Authors: Lee, Yunbeom, Kim, Jong Goo, Lee, Sang Jin, Muniyappan, Srinivasan, Kim, Tae Wu, Ki, Hosung, Kim, Hanui, Jo, Junbeom, Yun, So Ri, Lee, Hyosub, Lee, Kyung Won, Kim, Seong Ok, Cammarata, Marco, Ihee, Hyotcherl
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 16.06.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 631/45/535/1261; 639/638/439/944; 639/638/440/950; BASIC BIOLOGICAL SCIENCES; Coherent scattering; Electron density; Free electron lasers; Hemoglobin; Humanities and Social Sciences; Lasers; multidisciplinary; Myoglobins; NANOSCIENCE AND NANOTECHNOLOGY; photobiology; Physics; Proteins; reaction kinetics and dynamics; SAXS; Science; Science (multidisciplinary); Time dependence; DIMERIC HEMOGLOBIN; PROTEIN QUAKE; CAVITIES; KINETICS; LIGAND MIGRATION; TIME-RESOLVED CRYSTALLOGRAPHY; BINDING; STRUCTURAL DYNAMICS; PHOTODISSOCIATION
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-23947-7

Ultrafast motion of molecules, particularly the coherent motion, has been intensively investigated as a key factor guiding the reaction pathways. Recently, X-ray free-electron lasers (XFELs) have been utilized to elucidate the ultrafast motion of molecules. However, the studies on proteins using XFELs have been typically limited to the crystalline phase, and proteins in solution have rarely been investigated. Here we applied femtosecond time-resolved X-ray solution scattering (fs-TRXSS) and a structure refinement method to visualize the ultrafast motion of a protein. We succeeded in revealing detailed ultrafast structural changes of homodimeric hemoglobin involving the coherent motion. In addition to the motion of the protein itself, the time-dependent change of electron density of the hydration shell was tracked. Besides, the analysis on the fs-TRXSS data of myoglobin allows for observing the effect of the oligomeric state on the ultrafast coherent motion. Femtosecond time-resolved X-ray solution scattering (fs-TRXSS) measurements provide information on the structural dynamics of proteins in solution. Here, the authors present a structure refinement method for the analysis of fs-TRXSS data and use it to characterise the ultrafast structural changes of homodimeric haemoglobin.