6KAP

Carbonmonoxy human hemoglobin C in the R quaternary structure at 95 K: Light


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.194 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Direct observation of ligand migration within human hemoglobin at work.

Shibayama, N.Sato-Tomita, A.Ohki, M.Ichiyanagi, K.Park, S.Y.

(2020) Proc Natl Acad Sci U S A 117: 4741-4748

  • DOI: 10.1073/pnas.1913663117
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • Hemoglobin is one of the best-characterized proteins with respect to structure and function, but the internal ligand diffusion pathways remain obscure and controversial. Here we captured the CO migration processes in the tense (T), relaxed (R), and s ...

    Hemoglobin is one of the best-characterized proteins with respect to structure and function, but the internal ligand diffusion pathways remain obscure and controversial. Here we captured the CO migration processes in the tense (T), relaxed (R), and second relaxed (R2) quaternary structures of human hemoglobin by crystallography using a high-repetition pulsed laser technique at cryogenic temperatures. We found that in each quaternary structure, the photodissociated CO molecules migrate along distinct pathways in the α and β subunits by hopping between the internal cavities with correlated side chain motions of large nonpolar residues, such as α14Trp(A12), α105Leu(G12), β15Trp(A12), and β71Phe(E15). We also observe electron density evidence for the distal histidine [α58/β63His(E7)] swing-out motion regardless of the quaternary structure, although less evident in α subunits than in β subunits, suggesting that some CO molecules have escaped directly through the E7 gate. Remarkably, in T-state Fe(II)-Ni(II) hybrid hemoglobins in which either the α or β subunits contain Ni(II) heme that cannot bind CO, the photodissociated CO molecules not only dock at the cavities in the original Fe(II) subunit, but also escape from the protein matrix and enter the cavities in the adjacent Ni(II) subunit even at 95 K, demonstrating the high gas permeability and porosity of the hemoglobin molecule. Our results provide a comprehensive picture of ligand movements in hemoglobin and highlight the relevance of cavities, nonpolar residues, and distal histidines in facilitating the ligand migration.


    Organizational Affiliation

    Drug Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Tsurumi, 230-0045 Yokohama, Japan.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Hemoglobin subunit betaB146Homo sapiensMutation(s): 1 
Gene Names: HBB
Find proteins for P68871 (Homo sapiens)
Explore P68871 
Go to UniProtKB:  P68871
NIH Common Fund Data Resources
PHAROS  P68871
Protein Feature View
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  • Reference Sequence

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Hemoglobin subunit alphaA141Homo sapiensMutation(s): 0 
Gene Names: HBA1HBA2
Find proteins for P69905 (Homo sapiens)
Explore P69905 
Go to UniProtKB:  P69905
NIH Common Fund Data Resources
PHAROS  P69905
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download CCD File 
A, B
PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
CMO
Query on CMO

Download CCD File 
A, B
CARBON MONOXIDE
C O
UGFAIRIUMAVXCW-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.194 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.526α = 90
b = 53.526β = 90
c = 192.768γ = 90
Software Package:
Software NamePurpose
Aimlessdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction
CrysalisProdata reduction
PHASERphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Japan Society for the Promotion of ScienceJapanJP 16K07326

Revision History 

  • Version 1.0: 2020-02-19
    Type: Initial release
  • Version 1.1: 2020-03-04
    Changes: Database references
  • Version 1.2: 2020-03-18
    Changes: Database references