Details

Autor(en) / Beteiligte

• Mara, Michael W.
• Hadt, Ryan G.
• Reinhard, Marco Eli
• Kroll, Thomas
• Lim, Hyeongtaek
• Hartsock, Robert W.
• Alonso-Mori, Roberto
• Chollet, Matthieu
• Glownia, James M.
• Nelson, Silke
• Sokaras, Dimosthenis
• Kunnus, Kristjan
• Hodgson, Keith O.
• Hedman, Britt
• Bergmann, Uwe
• Gaffney, Kelly J.
• Solomon, Edward I.

Titel

Metalloprotein entatic control of ligand-metal bonds quantified by ultrafast x-ray spectroscopy

Ist Teil von

• Science (American Association for the Advancement of Science), 2017-06, Vol.356 (6344), p.1276-1280

Ort / Verlag

United States: American Association for the Advancement of Science

Erscheinungsjahr

2017

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The multifunctional protein cytochrome c (cyt c) plays key roles in electron transport and apoptosis, switching function by modulating bonding between a heme iron and the sulfur in a methionine residue. This Fe–S(Met) bond is too weak to persist in the absence of protein constraints. We ruptured the bond in ferrous cyt c using an optical laser pulse and monitored the bond reformation within the protein active site using ultrafast x-ray pulses from an x-ray free-electron laser, determining that the Fe–S(Met) bond enthalpy is ~4 kcal/mol stronger than in the absence of protein constraints. The 4 kcal/mol is comparable with calculations of stabilization effects in other systems, demonstrating how biological systems use an entatic state for modest yet accessible energetics to modulate chemical function.