The cysteine 34 residue of A1M/α1-microglobulin is essential for protection of irradiated cell cultures and reduction of carbonyl groups.
Rutardottir, Sigurbjörg LU ; Nilsson, E J C ; Pallon, Jan LU ; Gram, Magnus LU
and Åkerström, Bo
LU
(2013)
In Free Radical Research
47(6-7).
p.541-550
- Abstract
- α1-microglobulin (A1M) is a 26 kDa plasma and a tissue protein belonging to the lipocalin family. The reductase and free radical scavenger A1M has been shown to protect cells and extracellular matrix against oxidative and irradiation-induced damage. The reductase activity was previously shown to depend upon an unpaired cysteinyl side-chain, C34, and three lysyl side-chains, K92, 118, and 130, located around the open end of the lipocalin pocket. The aim of this work was to investigate whether the cell and matrix protection by A1M is a result of its reductase activity by using A1M-variants with site-directed mutations of the C34, K92, K118, and K130 positions. The results show that the C34 side-chain is an absolute requirement for protection... (More)
- α1-microglobulin (A1M) is a 26 kDa plasma and a tissue protein belonging to the lipocalin family. The reductase and free radical scavenger A1M has been shown to protect cells and extracellular matrix against oxidative and irradiation-induced damage. The reductase activity was previously shown to depend upon an unpaired cysteinyl side-chain, C34, and three lysyl side-chains, K92, 118, and 130, located around the open end of the lipocalin pocket. The aim of this work was to investigate whether the cell and matrix protection by A1M is a result of its reductase activity by using A1M-variants with site-directed mutations of the C34, K92, K118, and K130 positions. The results show that the C34 side-chain is an absolute requirement for protection of HepG2 cell cultures against alpha-particle irradiation-induced cell death, upregulation of stress response and cell cycle regulation genes. Mutation of C34 also resulted in loss of the reduction capacity toward heme- and hydrogen peroxide-oxidized collagen, and the radical species 2,2´-azino-bis (3-ethyl-benzo-thiazoline-6-sulphonic acid) (ABTS). Furthermore, mutation of C34 significantly suppressed the cell-uptake of A1M. The K92, K118, and K130 side-chains were of minor importance in cell protection and reduction of oxidized collagen but strongly influenced the reduction of the ABTS-radical. It is concluded that antioxidative protection of cells and collagen by A1M is totally dependent on its C34 amino acid residue. A model of the cell protection mechanism of A1M should be based on the redox activity of the free thiolyl group of the C34 side-chain and a regulatory role of the K92, K118, and K130 residues. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/3804933
- author
- Rutardottir, Sigurbjörg
LU
; Nilsson, E J C
; Pallon, Jan
LU
; Gram, Magnus
LU
and Åkerström, Bo
LU
- organization
- publishing date
- 2013
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Free Radical Research
- volume
- 47
- issue
- 6-7
- pages
- 541 - 550
- publisher
- Harwood Academic
- external identifiers
-
- wos:000319945700012
- pmid:23642167
- scopus:84878883367
- pmid:23642167
- ISSN
- 1029-2470
- DOI
- 10.3109/10715762.2013.801555
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Division of Infection Medicine (BMC) (013024020), Nuclear Physics (Faculty of Technology) (011013007)
- id
- 970502f3-d366-4061-a2cc-73c3bf56f148 (old id 3804933)
- alternative location
- http://www.ncbi.nlm.nih.gov/pubmed/23642167?dopt=Abstract
- date added to LUP
- 2016-04-01 10:00:38
- date last changed
- 2022-03-27 04:00:20
@article{970502f3-d366-4061-a2cc-73c3bf56f148,
abstract = {{α1-microglobulin (A1M) is a 26 kDa plasma and a tissue protein belonging to the lipocalin family. The reductase and free radical scavenger A1M has been shown to protect cells and extracellular matrix against oxidative and irradiation-induced damage. The reductase activity was previously shown to depend upon an unpaired cysteinyl side-chain, C34, and three lysyl side-chains, K92, 118, and 130, located around the open end of the lipocalin pocket. The aim of this work was to investigate whether the cell and matrix protection by A1M is a result of its reductase activity by using A1M-variants with site-directed mutations of the C34, K92, K118, and K130 positions. The results show that the C34 side-chain is an absolute requirement for protection of HepG2 cell cultures against alpha-particle irradiation-induced cell death, upregulation of stress response and cell cycle regulation genes. Mutation of C34 also resulted in loss of the reduction capacity toward heme- and hydrogen peroxide-oxidized collagen, and the radical species 2,2´-azino-bis (3-ethyl-benzo-thiazoline-6-sulphonic acid) (ABTS). Furthermore, mutation of C34 significantly suppressed the cell-uptake of A1M. The K92, K118, and K130 side-chains were of minor importance in cell protection and reduction of oxidized collagen but strongly influenced the reduction of the ABTS-radical. It is concluded that antioxidative protection of cells and collagen by A1M is totally dependent on its C34 amino acid residue. A model of the cell protection mechanism of A1M should be based on the redox activity of the free thiolyl group of the C34 side-chain and a regulatory role of the K92, K118, and K130 residues.}},
author = {{Rutardottir, Sigurbjörg and Nilsson, E J C and Pallon, Jan and Gram, Magnus and Åkerström, Bo}},
issn = {{1029-2470}},
language = {{eng}},
number = {{6-7}},
pages = {{541--550}},
publisher = {{Harwood Academic}},
series = {{Free Radical Research}},
title = {{The cysteine 34 residue of A1M/α1-microglobulin is essential for protection of irradiated cell cultures and reduction of carbonyl groups.}},
url = {{https://lup.lub.lu.se/search/files/1476541/4178758.pdf}},
doi = {{10.3109/10715762.2013.801555}},
volume = {{47}},
year = {{2013}},
}