Protein S binding in relation to the subunit composition of human C4b-binding protein
(1989) In FEBS Letters 259(1). p.6-53- Abstract
The human regulatory complement component C4b-binding protein (C4BP) circulates in plasma either as a free protein or in a bimolecular complex with the vitamin K-dependent protein S. The major form of C4BP is composed of 7 identical, disulfide-linked 70 kDa subunits (alpha-chains), the arrangement of which gives the C4BP molecule a spider-like appearance. Recently, we identified a unique 45 kDa subunit (beta-chain) in C4BP. We have now isolated a subpopulation of C4BP, which does not bind protein S. This C4BP species, which had a molecular weight slightly lower than that of the predominant form, was found to lack the beta-chain. Another lower molecular weight form of C4BP was also purified. It contained the beta-chain and was efficient... (More)
The human regulatory complement component C4b-binding protein (C4BP) circulates in plasma either as a free protein or in a bimolecular complex with the vitamin K-dependent protein S. The major form of C4BP is composed of 7 identical, disulfide-linked 70 kDa subunits (alpha-chains), the arrangement of which gives the C4BP molecule a spider-like appearance. Recently, we identified a unique 45 kDa subunit (beta-chain) in C4BP. We have now isolated a subpopulation of C4BP, which does not bind protein S. This C4BP species, which had a molecular weight slightly lower than that of the predominant form, was found to lack the beta-chain. Another lower molecular weight form of C4BP was also purified. It contained the beta-chain and was efficient in binding protein S. Its subunit composition was judged to comprise six alpha-chains and one beta-chain. These results indicate C4BP in plasma to be heterogeneous at a molecular level vis-a-vis subunit composition and/or protein S binding ability and provide support for the concept that the beta-chain of C4BP contains the single protein S binding site.
(Less)
- author
- Hillarp, A LU ; Hessing, M and Dahlbäck, B LU
- organization
- publishing date
- 1989-12-18
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Blotting, Western, Carrier Proteins/metabolism, Complement Inactivator Proteins, Complement System Proteins, Glycoproteins/metabolism, Humans, Macromolecular Substances, Molecular Weight, Protein Binding, Protein S
- in
- FEBS Letters
- volume
- 259
- issue
- 1
- pages
- 6 - 53
- publisher
- Wiley-Blackwell
- external identifiers
-
- pmid:2532155
- scopus:0024829563
- ISSN
- 0014-5793
- DOI
- 10.1016/0014-5793(89)81492-9
- language
- English
- LU publication?
- yes
- id
- 87ffea92-244b-4aa7-ab3d-ac57f42740a3
- date added to LUP
- 2022-08-29 10:36:32
- date last changed
- 2024-02-18 07:26:26
@article{87ffea92-244b-4aa7-ab3d-ac57f42740a3,
abstract = {{<p>The human regulatory complement component C4b-binding protein (C4BP) circulates in plasma either as a free protein or in a bimolecular complex with the vitamin K-dependent protein S. The major form of C4BP is composed of 7 identical, disulfide-linked 70 kDa subunits (alpha-chains), the arrangement of which gives the C4BP molecule a spider-like appearance. Recently, we identified a unique 45 kDa subunit (beta-chain) in C4BP. We have now isolated a subpopulation of C4BP, which does not bind protein S. This C4BP species, which had a molecular weight slightly lower than that of the predominant form, was found to lack the beta-chain. Another lower molecular weight form of C4BP was also purified. It contained the beta-chain and was efficient in binding protein S. Its subunit composition was judged to comprise six alpha-chains and one beta-chain. These results indicate C4BP in plasma to be heterogeneous at a molecular level vis-a-vis subunit composition and/or protein S binding ability and provide support for the concept that the beta-chain of C4BP contains the single protein S binding site.</p>}},
author = {{Hillarp, A and Hessing, M and Dahlbäck, B}},
issn = {{0014-5793}},
keywords = {{Blotting, Western; Carrier Proteins/metabolism; Complement Inactivator Proteins; Complement System Proteins; Glycoproteins/metabolism; Humans; Macromolecular Substances; Molecular Weight; Protein Binding; Protein S}},
language = {{eng}},
month = {{12}},
number = {{1}},
pages = {{6--53}},
publisher = {{Wiley-Blackwell}},
series = {{FEBS Letters}},
title = {{Protein S binding in relation to the subunit composition of human C4b-binding protein}},
url = {{http://dx.doi.org/10.1016/0014-5793(89)81492-9}},
doi = {{10.1016/0014-5793(89)81492-9}},
volume = {{259}},
year = {{1989}},
}