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Self-association of lysozyme as seen by magnetic relaxation dispersion

Gottschalk, Michael LU and Halle, Bertil LU (2003) In The Journal of Physical Chemistry Part B 107(31). p.7914-7922
Abstract
The pH and salt dependent self-association of hen egg-white lysozyme (HEWL) has been studied extensively, mainly by scattering techniques, but it has proven difficult to distinguish oligomerization from long-range interactions. Because HEWL is the principal model system in studies of protein crystallization, it is important to establish its oligomerization behavior unambiguously. Here, we address this problem with the aid of proton magnetic relaxation dispersion (MRD), which can determine the sizes and populations of coexisting oligomers with minimal influence of long-range interactions. We find that HEWL is monomeric at pH 4 and dimeric at pH 9. Dimers as well as a higher oligomer are formed also at pH 4 in the presence of K2SO4. The... (More)
The pH and salt dependent self-association of hen egg-white lysozyme (HEWL) has been studied extensively, mainly by scattering techniques, but it has proven difficult to distinguish oligomerization from long-range interactions. Because HEWL is the principal model system in studies of protein crystallization, it is important to establish its oligomerization behavior unambiguously. Here, we address this problem with the aid of proton magnetic relaxation dispersion (MRD), which can determine the sizes and populations of coexisting oligomers with minimal influence of long-range interactions. We find that HEWL is monomeric at pH 4 and dimeric at pH 9. Dimers as well as a higher oligomer are formed also at pH 4 in the presence of K2SO4. The dimer observed in solution has the same rotational correlation time as a dimer present in tetragonal HEWL crystals. The higher oligomer, consisting of about 16 HEWL monomers, is more abundant as the saturation limit is approached, but is suppressed by addition of sulfobetaine. It is also promoted by contaminating proteins, present in commercial HEWL preparations. These findings can explain why HEWL tends to form amorphous precipitates in the presence of sulfate and why crystallization of HEWL is facilitated by sulfobetaine. The MRD data also yield a residence time of 2 ns for several protein-associated water molecules, probably including the four-molecule cluster buried between the and subunits of HEWL. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
107
issue
31
pages
7914 - 7922
publisher
The American Chemical Society
external identifiers
  • wos:000184551300054
  • scopus:0042233475
ISSN
1520-5207
DOI
language
English
LU publication?
yes
id
d418a875-dd7f-401a-a8c4-f9c123d89e51 (old id 128030)
date added to LUP
2007-06-29 09:48:11
date last changed
2018-05-29 11:03:03
@article{d418a875-dd7f-401a-a8c4-f9c123d89e51,
  abstract     = {The pH and salt dependent self-association of hen egg-white lysozyme (HEWL) has been studied extensively, mainly by scattering techniques, but it has proven difficult to distinguish oligomerization from long-range interactions. Because HEWL is the principal model system in studies of protein crystallization, it is important to establish its oligomerization behavior unambiguously. Here, we address this problem with the aid of proton magnetic relaxation dispersion (MRD), which can determine the sizes and populations of coexisting oligomers with minimal influence of long-range interactions. We find that HEWL is monomeric at pH 4 and dimeric at pH 9. Dimers as well as a higher oligomer are formed also at pH 4 in the presence of K2SO4. The dimer observed in solution has the same rotational correlation time as a dimer present in tetragonal HEWL crystals. The higher oligomer, consisting of about 16 HEWL monomers, is more abundant as the saturation limit is approached, but is suppressed by addition of sulfobetaine. It is also promoted by contaminating proteins, present in commercial HEWL preparations. These findings can explain why HEWL tends to form amorphous precipitates in the presence of sulfate and why crystallization of HEWL is facilitated by sulfobetaine. The MRD data also yield a residence time of 2 ns for several protein-associated water molecules, probably including the four-molecule cluster buried between the and subunits of HEWL.},
  author       = {Gottschalk, Michael and Halle, Bertil},
  issn         = {1520-5207},
  language     = {eng},
  number       = {31},
  pages        = {7914--7922},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Self-association of lysozyme as seen by magnetic relaxation dispersion},
  url          = {http://dx.doi.org/},
  volume       = {107},
  year         = {2003},
}