Advanced

Physico-chemical properties of the N-terminally truncated L68Q cystatin C found in amyloid deposits of brain haemorrhage patients.

Gerhartz, Bernd and Abrahamson, Magnus LU (2002) In Biological Chemistry1996-01-01+01:00 383(2). p.301-305
Abstract
Cystatin C, a major extracellular cysteine proteinase inhibitor, is deposited as amyloid in brain haemorrhage patients with hereditary cystatin C amyloid angiopathy (HCCAA). A disease-causing mutation on the genetic level results in the substitution Leu68-->Gln (L68Q) in cystatin C, which causes protein instability. Besides carrying the L68Q substitution, cystatin C in amyloid deposits isolated from patients is N-terminally truncated by 10 amino acids. To elucidate the role of the N-terminal truncation for protein stability and aggregation properties, (delta1-10,L68Q)-cystatin C was produced in an Escherichia coli expression system and characterised. Unlike wild-type cystatin C, this variant rapidly dimerised under physiological... (More)
Cystatin C, a major extracellular cysteine proteinase inhibitor, is deposited as amyloid in brain haemorrhage patients with hereditary cystatin C amyloid angiopathy (HCCAA). A disease-causing mutation on the genetic level results in the substitution Leu68-->Gln (L68Q) in cystatin C, which causes protein instability. Besides carrying the L68Q substitution, cystatin C in amyloid deposits isolated from patients is N-terminally truncated by 10 amino acids. To elucidate the role of the N-terminal truncation for protein stability and aggregation properties, (delta1-10,L68Q)-cystatin C was produced in an Escherichia coli expression system and characterised. Unlike wild-type cystatin C, this variant rapidly dimerised under physiological conditions. Two unfolding intermediates of (delta1-10,L68Q)-cystatin C were identified, under the same pH and ionic strength conditions as required to form intermediates of full-length L68Q cystatin C. No evidence was found that the N-terminal truncation per se alters protein stability and leads to higher forms of aggregation. Monomeric as well as dimeric L68Q cystatin C incubated with neutrophil elastase was truncated as in HCCAA patients' amyloid. A protein variant with a thrombin cleavage site placed in front of residue Gly11 in L68Q cystatin C was constructed and used to confirm that the N-terminal segment is similarly accessible to proteinases in the monomeric and dimeric states of L68Q cystatin C. Thus, the N-terminal segment of L68Q cystatin C is exposed to proteolytic attack and does not seem to be involved in intramolecular contacts leading to dimerisation or higher-order aggregation. We conclude that the N-terminal truncation likely is an event secondary to amyloid formation, and of no relevance for the development of HCCAA. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biological Chemistry1996-01-01+01:00
volume
383
issue
2
pages
301 - 305
publisher
De Gruyter
external identifiers
  • pmid:11934268
  • wos:000174545300008
  • scopus:0036118589
ISSN
1437-4315
language
English
LU publication?
yes
id
c5ca64c6-e232-42ef-ade8-a7ee67864876 (old id 107405)
alternative location
http://www.degruyter.de/journals/bc/272_3065_ENU_h.htm
date added to LUP
2007-07-05 08:53:20
date last changed
2017-01-01 04:36:09
@article{c5ca64c6-e232-42ef-ade8-a7ee67864876,
  abstract     = {Cystatin C, a major extracellular cysteine proteinase inhibitor, is deposited as amyloid in brain haemorrhage patients with hereditary cystatin C amyloid angiopathy (HCCAA). A disease-causing mutation on the genetic level results in the substitution Leu68-->Gln (L68Q) in cystatin C, which causes protein instability. Besides carrying the L68Q substitution, cystatin C in amyloid deposits isolated from patients is N-terminally truncated by 10 amino acids. To elucidate the role of the N-terminal truncation for protein stability and aggregation properties, (delta1-10,L68Q)-cystatin C was produced in an Escherichia coli expression system and characterised. Unlike wild-type cystatin C, this variant rapidly dimerised under physiological conditions. Two unfolding intermediates of (delta1-10,L68Q)-cystatin C were identified, under the same pH and ionic strength conditions as required to form intermediates of full-length L68Q cystatin C. No evidence was found that the N-terminal truncation per se alters protein stability and leads to higher forms of aggregation. Monomeric as well as dimeric L68Q cystatin C incubated with neutrophil elastase was truncated as in HCCAA patients' amyloid. A protein variant with a thrombin cleavage site placed in front of residue Gly11 in L68Q cystatin C was constructed and used to confirm that the N-terminal segment is similarly accessible to proteinases in the monomeric and dimeric states of L68Q cystatin C. Thus, the N-terminal segment of L68Q cystatin C is exposed to proteolytic attack and does not seem to be involved in intramolecular contacts leading to dimerisation or higher-order aggregation. We conclude that the N-terminal truncation likely is an event secondary to amyloid formation, and of no relevance for the development of HCCAA.},
  author       = {Gerhartz, Bernd and Abrahamson, Magnus},
  issn         = {1437-4315},
  language     = {eng},
  number       = {2},
  pages        = {301--305},
  publisher    = {De Gruyter},
  series       = {Biological Chemistry1996-01-01+01:00},
  title        = {Physico-chemical properties of the N-terminally truncated L68Q cystatin C found in amyloid deposits of brain haemorrhage patients.},
  volume       = {383},
  year         = {2002},
}