中国物理B ›› 2015, Vol. 24 ›› Issue (12): 128705-128705.doi: 10.1088/1674-1056/24/12/128705

• SPECIAL TOPIC—8th IUPAP International Conference on Biological Physics • 上一篇    下一篇

Comparison of ligand migration and binding in heme proteins of the globin family

Karin Nienhausa, G. Ulrich Nienhausa b c   

  1. a Institute of Applied Physics (APH), Karlsruhe Institute of Technology (KIT), D-76049 Karlsruhe, Germany;
    b Institute of Nanotechnology (INT) and Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe, Germany;
    c Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Il 61801, USA
  • 收稿日期:2015-01-22 修回日期:2015-03-20 出版日期:2015-12-05 发布日期:2015-12-05
  • 通讯作者: G. Ulrich Nienhaus E-mail:uli@illinois.edu

Comparison of ligand migration and binding in heme proteins of the globin family

Karin Nienhausa, G. Ulrich Nienhausa b c   

  1. a Institute of Applied Physics (APH), Karlsruhe Institute of Technology (KIT), D-76049 Karlsruhe, Germany;
    b Institute of Nanotechnology (INT) and Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe, Germany;
    c Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Il 61801, USA
  • Received:2015-01-22 Revised:2015-03-20 Online:2015-12-05 Published:2015-12-05
  • Contact: G. Ulrich Nienhaus E-mail:uli@illinois.edu

摘要: The binding of small diatomic ligands such as carbon monoxide or dioxygen to heme proteins is among the simplest biological processes known. Still, it has taken many decades to understand the mechanistic aspects of this process in full detail. Here, we compare ligand binding in three heme proteins of the globin family, myoglobin, a dimeric hemoglobin, and neuroglobin. The combination of structural, spectroscopic, and kinetic experiments over many years by many laboratories has revealed common properties of globins and a clear mechanistic picture of ligand binding at the molecular level. In addition to the ligand binding site at the heme iron, a primary ligand docking site exists that ensures efficient ligand binding to and release from the heme iron. Additional, secondary docking sites can greatly facilitate ligand escape after its dissociation from the heme. Although there is only indirect evidence at present, a preformed histidine gate appears to exist that allows ligand entry to and exit from the active site. The importance of these features can be assessed by studies involving modified proteins (via site-directed mutagenesis) and comparison with heme proteins not belonging to the globin family.

关键词: flash photolysis, ligand binding, time-resolved spectroscopy, heme protein

Abstract: The binding of small diatomic ligands such as carbon monoxide or dioxygen to heme proteins is among the simplest biological processes known. Still, it has taken many decades to understand the mechanistic aspects of this process in full detail. Here, we compare ligand binding in three heme proteins of the globin family, myoglobin, a dimeric hemoglobin, and neuroglobin. The combination of structural, spectroscopic, and kinetic experiments over many years by many laboratories has revealed common properties of globins and a clear mechanistic picture of ligand binding at the molecular level. In addition to the ligand binding site at the heme iron, a primary ligand docking site exists that ensures efficient ligand binding to and release from the heme iron. Additional, secondary docking sites can greatly facilitate ligand escape after its dissociation from the heme. Although there is only indirect evidence at present, a preformed histidine gate appears to exist that allows ligand entry to and exit from the active site. The importance of these features can be assessed by studies involving modified proteins (via site-directed mutagenesis) and comparison with heme proteins not belonging to the globin family.

Key words: flash photolysis, ligand binding, time-resolved spectroscopy, heme protein

中图分类号:  (Protein-ligand interactions)

  • 87.15.kp
87.64.-t (Spectroscopic and microscopic techniques in biophysics and medical physics) 87.80.-y (Biophysical techniques (research methods))