Analysis of binding sites on complement factor I that are required for its activity.
Nilsson, Sara LU ; Nita, Izabela LU ; Walther, Lisa LU ; Groeneveld, Tom LU ; Trouw, Leendert LU ; Villoutreix, Bruno O and Blom, Anna LU
(2010)
In Journal of Biological Chemistry
285.
p.6235-6245
- Abstract
- The central complement inhibitor factor I (FI) degrades activated complement factors C4b and C3b in the presence of cofactors such as C4b-binding protein, factor H, complement receptor 1 and membrane cofactor protein. FI is a serine protease composed of two chains; the light chain comprises the serine protease domain, while the heavy chain contains several domains: the FI and membrane attack complex domain (FIMAC), CD5, low density lipoprotein receptor 1 (LDLr1) and LDLr2 domains. In order to understand better how FI acts as a complement inhibitor, we used homology-based models of FI domains to predict potential binding sites. Specific amino acids were then mutated to yield 16 well-expressed mutants, which were then purified from media of... (More)
- The central complement inhibitor factor I (FI) degrades activated complement factors C4b and C3b in the presence of cofactors such as C4b-binding protein, factor H, complement receptor 1 and membrane cofactor protein. FI is a serine protease composed of two chains; the light chain comprises the serine protease domain, while the heavy chain contains several domains: the FI and membrane attack complex domain (FIMAC), CD5, low density lipoprotein receptor 1 (LDLr1) and LDLr2 domains. In order to understand better how FI acts as a complement inhibitor, we used homology-based models of FI domains to predict potential binding sites. Specific amino acids were then mutated to yield 16 well-expressed mutants, which were then purified from media of eukaryotic cells for functional analyses. The Michaelis constant (Km) of all FI mutants towards a small substrate was not altered while some mutants showed increased maximum initial velocity (Vmax). All the mutations in the FIMAC domain affected the ability of FI to degrade C4b and C3b irrespective of the cofactor used whereas only some mutations in the CD5 and LDLr1/2 domains had similar effect. These same mutants also showed impaired binding to C3met. In conclusion, the FIMAC domain appears to harbor the main binding sites important for the ability of FI to degrade C4b and C3b. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1541415
- author
- Nilsson, Sara
LU
; Nita, Izabela
LU
; Walther, Lisa
LU
; Groeneveld, Tom
LU
; Trouw, Leendert
LU
; Villoutreix, Bruno O
and Blom, Anna
LU
- organization
- publishing date
- 2010
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Biological Chemistry
- volume
- 285
- pages
- 6235 - 6245
- publisher
- American Society for Biochemistry and Molecular Biology
- external identifiers
-
- wos:000275367500028
- pmid:20044478
- scopus:77949909418
- pmid:20044478
- ISSN
- 1083-351X
- DOI
- 10.1074/jbc.M109.097212
- language
- English
- LU publication?
- yes
- id
- 0bafbf1d-2493-4c4b-bc39-00806d3e3bf9 (old id 1541415)
- alternative location
- http://www.ncbi.nlm.nih.gov/pubmed/20044478?dopt=Abstract
- date added to LUP
- 2016-04-04 08:57:08
- date last changed
- 2022-03-23 03:41:22
@article{0bafbf1d-2493-4c4b-bc39-00806d3e3bf9,
abstract = {{The central complement inhibitor factor I (FI) degrades activated complement factors C4b and C3b in the presence of cofactors such as C4b-binding protein, factor H, complement receptor 1 and membrane cofactor protein. FI is a serine protease composed of two chains; the light chain comprises the serine protease domain, while the heavy chain contains several domains: the FI and membrane attack complex domain (FIMAC), CD5, low density lipoprotein receptor 1 (LDLr1) and LDLr2 domains. In order to understand better how FI acts as a complement inhibitor, we used homology-based models of FI domains to predict potential binding sites. Specific amino acids were then mutated to yield 16 well-expressed mutants, which were then purified from media of eukaryotic cells for functional analyses. The Michaelis constant (Km) of all FI mutants towards a small substrate was not altered while some mutants showed increased maximum initial velocity (Vmax). All the mutations in the FIMAC domain affected the ability of FI to degrade C4b and C3b irrespective of the cofactor used whereas only some mutations in the CD5 and LDLr1/2 domains had similar effect. These same mutants also showed impaired binding to C3met. In conclusion, the FIMAC domain appears to harbor the main binding sites important for the ability of FI to degrade C4b and C3b.}},
author = {{Nilsson, Sara and Nita, Izabela and Walther, Lisa and Groeneveld, Tom and Trouw, Leendert and Villoutreix, Bruno O and Blom, Anna}},
issn = {{1083-351X}},
language = {{eng}},
pages = {{6235--6245}},
publisher = {{American Society for Biochemistry and Molecular Biology}},
series = {{Journal of Biological Chemistry}},
title = {{Analysis of binding sites on complement factor I that are required for its activity.}},
url = {{http://dx.doi.org/10.1074/jbc.M109.097212}},
doi = {{10.1074/jbc.M109.097212}},
volume = {{285}},
year = {{2010}},
}