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Insertion of Heme b into the Structure of the Cys34-Carbamidomethylated Human Lipocalin a1-Microglobulin: Formation of a [(Heme)2(a1-Microglobulin)]3 Complex

Siebel, Judith F.; Kosinsky, Robyn L.; Åkerström, Bo LU and Knipp, Markus (2012) In ChemBioChem 13(6). p.879-887
Abstract
a1-Microglobulin (a1m) is a 26 kDa plasma and tissue protein belonging to the lipocalin protein family. Previous investigations indicate that the protein interacts with heme and suggest that it has a function in heme metabolism. However, detailed characterizations of the a1mheme interactions are lacking. Here, we report for the first time the preparation and analysis of a stable a1mheme complex upon carbamidomethylation of the reactive Cys34 by using recombinantly expressed human a1m. Analytical size-exclusion chromatography coupled with a diode-array absorbance spectrophotometry demonstrates that at first an a1mheme monomer is formed. Subsequently, a second heme triggers oligomerization that leads to trimerization. The resulting... (More)
a1-Microglobulin (a1m) is a 26 kDa plasma and tissue protein belonging to the lipocalin protein family. Previous investigations indicate that the protein interacts with heme and suggest that it has a function in heme metabolism. However, detailed characterizations of the a1mheme interactions are lacking. Here, we report for the first time the preparation and analysis of a stable a1mheme complex upon carbamidomethylation of the reactive Cys34 by using recombinantly expressed human a1m. Analytical size-exclusion chromatography coupled with a diode-array absorbance spectrophotometry demonstrates that at first an a1mheme monomer is formed. Subsequently, a second heme triggers oligomerization that leads to trimerization. The resulting (a1m[heme]2)3 complex was characterized by resonance Raman and EPR spectroscopy, which support the presence of two ferrihemes, thus indicating an unusual spin-state admixed ground state with S=3/2, 5/2. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
heme proteins, homotrimers, lipocalin, metalloproteins, microglobulins, spin admixture
in
ChemBioChem
volume
13
issue
6
pages
879 - 887
publisher
John Wiley & Sons
external identifiers
  • wos:000302609100018
  • scopus:84859597177
ISSN
1439-4227
DOI
10.1002/cbic.201100808
language
English
LU publication?
yes
id
9010a33b-8c6d-485c-9698-4cebf013e68a (old id 2571583)
date added to LUP
2012-06-01 08:57:17
date last changed
2017-10-22 03:03:12
@article{9010a33b-8c6d-485c-9698-4cebf013e68a,
  abstract     = {a1-Microglobulin (a1m) is a 26 kDa plasma and tissue protein belonging to the lipocalin protein family. Previous investigations indicate that the protein interacts with heme and suggest that it has a function in heme metabolism. However, detailed characterizations of the a1mheme interactions are lacking. Here, we report for the first time the preparation and analysis of a stable a1mheme complex upon carbamidomethylation of the reactive Cys34 by using recombinantly expressed human a1m. Analytical size-exclusion chromatography coupled with a diode-array absorbance spectrophotometry demonstrates that at first an a1mheme monomer is formed. Subsequently, a second heme triggers oligomerization that leads to trimerization. The resulting (a1m[heme]2)3 complex was characterized by resonance Raman and EPR spectroscopy, which support the presence of two ferrihemes, thus indicating an unusual spin-state admixed ground state with S=3/2, 5/2.},
  author       = {Siebel, Judith F. and Kosinsky, Robyn L. and Åkerström, Bo and Knipp, Markus},
  issn         = {1439-4227},
  keyword      = {heme proteins,homotrimers,lipocalin,metalloproteins,microglobulins,spin admixture},
  language     = {eng},
  number       = {6},
  pages        = {879--887},
  publisher    = {John Wiley & Sons},
  series       = {ChemBioChem},
  title        = {Insertion of Heme b into the Structure of the Cys34-Carbamidomethylated Human Lipocalin a1-Microglobulin: Formation of a [(Heme)2(a1-Microglobulin)]3 Complex},
  url          = {http://dx.doi.org/10.1002/cbic.201100808},
  volume       = {13},
  year         = {2012},
}