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Structural characterization of inter-alpha-inhibitor. Evidence for an extended shape

Blom, A M; Mörgelin, Matthias LU ; Oyen, M; Jarvet, J and Fries, E (1999) In Journal of Biological Chemistry 274(1). p.298-304
Abstract
Inter-alpha-inhibitor (IalphaI) is a 180-kDa serum protein consisting of three polypeptides. Two of these, the heavy chains 1 and 2 (H1 and H2), are of 75-80 kDa and have similar amino acid sequences. The third polypeptide, bikunin, has a molecular mass of 25 kDa and contains a 7-kDa chondroitin sulfate chain that is covalently linked to the C-terminal amino acid residues of H1 and H2. IalphaI has been shown to be required for the formation of the hyaluronan-containing extracellular matrix of certain cell types. How IalphaI exerts this function is not known, but it appears that upon interaction with cells, the heavy chains are released and become covalently linked to hyaluronan. Our results indicate that IalphaI and its heavy chains are... (More)
Inter-alpha-inhibitor (IalphaI) is a 180-kDa serum protein consisting of three polypeptides. Two of these, the heavy chains 1 and 2 (H1 and H2), are of 75-80 kDa and have similar amino acid sequences. The third polypeptide, bikunin, has a molecular mass of 25 kDa and contains a 7-kDa chondroitin sulfate chain that is covalently linked to the C-terminal amino acid residues of H1 and H2. IalphaI has been shown to be required for the formation of the hyaluronan-containing extracellular matrix of certain cell types. How IalphaI exerts this function is not known, but it appears that upon interaction with cells, the heavy chains are released and become covalently linked to hyaluronan. Our results indicate that IalphaI and its heavy chains are extended molecules; thus, upon electron microscopy, IalphaI appeared to consist of two globular domains connected by a thin structure 31-nm long and the isolated heavy chains of a globular domain and a "tail" about 15-nm long. Analysis of the heavy chains by partial proteolysis showed that the C-terminal halves are particularly sensitive to hydrolysis indicating that they are loosely folded. Furthermore, electron microscopy showed that partially degraded heavy chains lacked the extended regions. Taken together, these results suggest that the N-terminal half of the heavy chains forms a globular domain, whereas the other half has an extended and loosely folded structure. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Biological Chemistry
volume
274
issue
1
pages
298 - 304
publisher
ASBMB
external identifiers
  • pmid:9867844
ISSN
1083-351X
language
English
LU publication?
yes
id
188c1ceb-58d8-4330-883b-372e5bcf07d1 (old id 1115491)
alternative location
http://www.jbc.org/cgi/content/full/274/1/298
date added to LUP
2008-07-08 10:00:41
date last changed
2016-04-15 19:12:12
@article{188c1ceb-58d8-4330-883b-372e5bcf07d1,
  abstract     = {Inter-alpha-inhibitor (IalphaI) is a 180-kDa serum protein consisting of three polypeptides. Two of these, the heavy chains 1 and 2 (H1 and H2), are of 75-80 kDa and have similar amino acid sequences. The third polypeptide, bikunin, has a molecular mass of 25 kDa and contains a 7-kDa chondroitin sulfate chain that is covalently linked to the C-terminal amino acid residues of H1 and H2. IalphaI has been shown to be required for the formation of the hyaluronan-containing extracellular matrix of certain cell types. How IalphaI exerts this function is not known, but it appears that upon interaction with cells, the heavy chains are released and become covalently linked to hyaluronan. Our results indicate that IalphaI and its heavy chains are extended molecules; thus, upon electron microscopy, IalphaI appeared to consist of two globular domains connected by a thin structure 31-nm long and the isolated heavy chains of a globular domain and a "tail" about 15-nm long. Analysis of the heavy chains by partial proteolysis showed that the C-terminal halves are particularly sensitive to hydrolysis indicating that they are loosely folded. Furthermore, electron microscopy showed that partially degraded heavy chains lacked the extended regions. Taken together, these results suggest that the N-terminal half of the heavy chains forms a globular domain, whereas the other half has an extended and loosely folded structure.},
  author       = {Blom, A M and Mörgelin, Matthias and Oyen, M and Jarvet, J and Fries, E},
  issn         = {1083-351X},
  language     = {eng},
  number       = {1},
  pages        = {298--304},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {Structural characterization of inter-alpha-inhibitor. Evidence for an extended shape},
  volume       = {274},
  year         = {1999},
}