1J3Z

Direct observation of photolysis-induced tertiary structural changes in human haemoglobin; Crystal structure of alpha(Fe-CO)-beta(Ni) hemoglobin (laser unphotolysed)

Summary for 1J3Z

• Entry DOI: 10.2210/pdb1j3z/pdb
• Related: 1J3Y 1J40 1J41
• Descriptor: Hemoglobin alpha Chain, Hemoglobin beta Chain, PROTOPORPHYRIN IX CONTAINING FE, ... (7 entities in total)
• Functional Keywords: tertiary structure changes, crystal photolysis, riken structural genomics/proteomics initiative, rsgi, structural genomics, oxygen storage-transport complex, oxygen storage/transport
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 8
• Total formula weight: 129385.68

Authors

Adachi, S.,Park, S.-Y.,Tame, J.R.H.,Shiro, Y.,Shibayama, N.,RIKEN Structural Genomics/Proteomics Initiative (RSGI) (deposition date: 2003-02-21, release date: 2003-07-22, Last modification date: 2024-12-25)

Primary citation

Adachi, S.,Park, S.-Y.,Tame, J.R.H.,Shiro, Y.,Shibayama, N.
Direct observation of photolysis-induced tertiary structural changes in hemoglobin
Proc.Natl.Acad.Sci.USA, 100:7039-7044, 2003

PubMed Abstract: Human Hb, an alpha2beta2 tetrameric oxygen transport protein that switches from a T (tense) to an R (relaxed) quaternary structure during oxygenation, has long served as a model for studying protein allostery in general. Time-resolved spectroscopic measurements after photodissociation of CO-liganded Hb have played a central role in exploring both protein dynamical responses and molecular cooperativity, but the direct visualization and the structural consequences of photodeligation have not yet been reported. Here we present an x-ray study of structural changes induced by photodissociation of half-liganded T-state and fully liganded R-state human Hb at cryogenic temperatures (25-35 K). On photodissociation of CO, structural changes involving the heme and the F-helix are more marked in the alpha subunit than in the beta subunit, and more subtle in the R state than in the T state. Photodeligation causes a significant sliding motion of the T-state beta heme. Our results establish that the structural basis of the low affinity of the T state is radically different between the subunits, because of differences in the packing and chemical tension at the hemes.

PubMed: 12773618
DOI: 10.1073/pnas.1230629100

Experimental method

X-RAY DIFFRACTION (1.6 Å)