ISDA: 2BLH

Deposition Date 2005-03-04

Release Date 2005-04-06

Last Version Date 2024-05-08

Entry Detail

PDB ID:

2BLH

Keywords:

OXYGEN TRANSPORT

Title:

Ligand Migration and Protein Fluctuations in Myoglobin Mutant L29W

Biological Source:

Source Organism:

PHYSETER CATODON (Taxon ID: 9755)

Host Organism:

ESCHERICHIA COLI

Method Details:

Experimental Method:

X-RAY DIFFRACTION

Resolution:

1.77 Å

R-Value Free:

0.20

R-Value Work:

0.18

R-Value Observed:

0.18

Space Group:

P 6

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Macromolecular Entities

Structures with similar UniProt ID

Protein Blast

Polymer Type:polypeptide(L)
Molecule:MYOGLOBIN
Gene (Uniprot):MB
Mutagens:YES
Chain IDs:A
Chain Length:153
Number of Molecules:1
Biological Source:PHYSETER CATODON

UniProt ID:P02185 Pfam ID:PF00042

Ligand Molecules

HEM

Primary Citation

Ligand Migration and Protein Fluctuations in Myoglobin Mutant L29W

Nienhaus, K, Ostermann, A, Nienhaus, G.U, Parak, F.G, Schmidt, M.Show

Biochemistry 44 5095 ? (2005)

PMID: 15794647 DOI: 10.1021/BI047513T

Abstact

We have determined eight X-ray structures of myoglobin mutant L29W at various experimental conditions. In addition, infrared spectroscopic experiments are presented, which are discussed in the light of the X-ray structures. Two distinct conformations of the CO-ligated protein were identified, giving rise to two stretching bands of heme-bound CO. If L29W MbCO crystals are illuminated around 180 K, a deoxy species is formed. The CO molecules migrate to the proximal side of the heme and remain trapped in the so-called Xe1 cavity upon temperature decrease to 105 K. The structure of this photoproduct is almost identical to the equilibrium high-temperature deoxy Mb structure. If the temperature is cycled to increasingly higher values, CO recombination is observed. Three intermediate structures have been determined during the rebinding process. Efficient recombination occurs only above 180 K, the characteristic temperature for the onset of protein dynamics. Rebinding is remarkably slow because bulky residues His64 and Trp29 block important migration pathways of the CO molecule.

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