**************** The 15th., Lab Seminar ****************************

Date: Thu, December 13, 2007 PM 2:30-

Place: No.616 Seminar room
　　　　　　 Graduate School of Information Science

Speaker: Chiharu Iwahashi

Title: Internal cavities and ligand passageways in human hemoglobin 
characterized by molecular dynamics simulations
(Liliane Mouawad, Jean-Didier Marechal, David Perahia)

Abstract:
 Molecular dynamics simulations of the unliganded T state of human 
hemoglobin showed the existence of a spontaneous, very wide cavity 
on the distal side of the α subunit. This cavity of three tunnels 
spreading from the vicinity of the iron atom (the ligand binding site) 
to the surface of the subunit, constituting possible passageways for 
the entrance of the ligand. A fourth passageway was characterized 
due to the trajectory of water molecules entering or leaving the 
heme pocket. Analogous passages were observed in the β subunits. 
They all appear and disappear dynamically, although some parts of 
them are more persistent along the trajectories. The most persistent 
regions within these tunnels correspond to all the xenon docking sites 
of human cytoglobin and to some of those of sperm whale and horse 
heart myoglobins and group I truncated hemoglobins.

*******************************************************************