Dehaloperoxidase-hemoglobin from Amphitrite ornata is primarily a monomer in solution.
J Phys Chem B
; 115(14): 4266-72, 2011 Apr 14.
Article
em En
| MEDLINE
| ID: mdl-21417234
ABSTRACT
The crystal structures of the dehaloperoxidase-hemoglobin from A. ornata (DHP A) each report a crystallographic dimer in the unit cell. Yet, the largest dimer interface observed is 450 Å(2), an area significantly smaller than the typical value of 1200-2000 Å(2) and in contrast to the extensive interface region of other known dimeric hemoglobins. To examine the oligomerization state of DHP A in solution, we used gel permeation by fast protein liquid chromatography and small-angle X-ray scattering (SAXS). Gel permeation experiments demonstrate that DHP A elutes as a monomer (15.5 kDa) and can be separated from green fluorescent protein, which has a molar mass of 27 kDa, near the 31 kDa expected for the DHP A dimer. By SAXS, we found that DHP A is primarily monomeric in solution, but with a detectable level of dimer (~10%), under all conditions studied up to a protein concentration of 3.0 mM. These concentrations are likely 10-100-fold lower than the K(d) for dimer formation. Additionally, there was no significant effect either on the overall conformation of DHP A or its monomer-dimer equilibrium upon addition of the DHP A inhibitor, 4-iodophenol.
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Base de dados:
MEDLINE
Assunto principal:
Peroxidases
/
Poliquetos
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Hemoglobinas
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article