HOMEPRODUCTSSERVICESCOMPANYCONTACTFAQResearchDictionaryPharmaMobileSign Up FREE or Login

Distinct properties of wild-type and the amyloidogenic human cystatin C variant of hereditary cerebral hemorrhage with amyloidosis, Icelandic type.

Abstract
Variant human cystatin C (L68Q) is an amyloidogenic protein. It deposits in the cerebral vasculature of Icelandic patients with cerebral amyloid angiopathy, leading to stroke. Wild-type and variant cystatin C are cysteine proteinase inhibitors which form concentration dependent inactive dimers; however, variant cystatin C dimerizes at lower concentrations and has an increased susceptibility to a serine protease. We studied the effect of the L68Q amino acid substitution on cystatin C properties, utilizing full length cystatin C purified in mild conditions from media of cells stably transfected with either the wild-type or variant cystatin C genes. The variant cystatin C forms fibrils in vitro detectable by electron microscopy in conditions in which the wild-type protein forms amorphous aggregates. We also show by circular dichroism, steady-state fluorescence and Fourier-transformed infrared spectroscopy that the amino acid substitution modifies cystatin C structure by destabilizing alpha-helical structures and exposing the tryptophan residue to a more polar environment, yielding a more unfolded molecule. These spectral changes demonstrate that variant cystatin C has a three-dimensional structure different from that of the wild-type protein. The structural differences between variant and wild-type cystatin C account for the susceptibility of the variant protein to unfolding, proteolysis and fibrillogenesis.
AuthorsM Calero, M Pawlik, C Soto, E M Castaño, E M Sigurdsson, A Kumar, G Gallo, B Frangione, E Levy
JournalJournal of neurochemistry (J Neurochem) Vol. 77 Issue 2 Pg. 628-37 (Apr 2001) ISSN: 0022-3042 [Print] United States
PMID11299325 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
Chemical References
  • CST3 protein, human
  • Codon
  • Cystatin C
  • Cystatins
  • Nerve Tissue Proteins
  • Recombinant Fusion Proteins
  • Glutamine
  • Leucine
Topics
  • Amino Acid Substitution
  • Animals
  • Cerebral Amyloid Angiopathy (genetics, metabolism)
  • Cerebral Hemorrhage (genetics, metabolism)
  • Chemistry, Physical
  • Chickens
  • Circular Dichroism
  • Codon (genetics)
  • Computer Simulation
  • Cystatin C
  • Cystatins (chemistry, genetics)
  • Dimerization
  • Glutamine (chemistry)
  • Humans
  • Leucine (chemistry)
  • Microscopy, Electron
  • Models, Molecular
  • Mutation, Missense
  • Nerve Tissue Proteins (chemistry, genetics)
  • Physicochemical Phenomena
  • Protein Conformation
  • Protein Folding
  • Protein Structure, Secondary
  • Recombinant Fusion Proteins (chemistry)
  • Species Specificity
  • Spectroscopy, Fourier Transform Infrared
  • Transfection

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research network!


Choose Username:
Email:
Password:
Verify Password: