2ZLV: Horse Methemoglobin High Salt, Ph 7.0 (79% Relative Humidity)

The crystal structure of high-salt horse methaemoglobin has been determined at environmental relative humidities (r.h.) of 88, 79, 75 and 66%. The molecule is in the R state in the native and the r.h. 88% crystals. At r.h. 79%, the water content of the crystal is reduced and the molecule appears to move towards the R2 state. The crystals undergo a water-mediated transformation involving a doubling of one of the unit-cell parameters and an increase in water content when the environmental humidity is further reduced to r.h. 75%. The water content is now similar to that in the native crystals and the molecules are in the R state. The crystal structure at r.h. 66% is similar, but not identical, to that at r.h. 75%, but the solvent content is substantially reduced and the molecules have a quaternary structure that is in between those corresponding to the R and R2 states. Thus, variation in hydration leads to variation in the quaternary structure. Furthermore, partial dehydration appears to shift the structure from the R state to the R2 state. This observation is in agreement with the earlier conclusion that the changes in protein structure that accompany partial dehydration are similar to those that occur during protein action.
PDB ID: 2ZLVDownload
MMDB ID: 65092
PDB Deposition Date: 2008/4/10
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 2ZLV: tetrameric; determined by author and by software (PISA)
Molecular Components in 2ZLV
Label Count Molecule
Proteins (4 molecules)
Hemoglobin Subunit Alpha(Gene symbol: HBA)
Molecule annotation
Hemoglobin Subunit Beta(Gene symbol: HBB)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB