Linked Life Data

19427320

Source:http://linkedlifedata.com/resource/pubmed/id/19427320

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2009-6-15
pubmed:abstractText
Human islet amyloid polypeptide (hIAPP), which is considered the primary culprit for beta-cell loss in type 2 diabetes mellitus patients, is synthesized in beta-cells of the pancreas from its precursor pro-islet amyloid polypeptide (proIAPP), which may be important in early intracellular amyloid formation as well. We compare the amyloidogenic propensities and conformational properties of proIAPP and hIAPP in the presence of negatively charged lipid membranes, which have been discussed as loci of initiation of the fibrillation reaction. Circular dichroism studies verify the initial secondary structures of proIAPP and hIAPP to be predominantly unordered with small amounts of ordered secondary structure elements, and exhibit minor differences between these two peptides only. Using attenuated total reflection-Fourier transform infrared spectroscopy and thioflavin T fluorescence spectroscopy, as well as atomic force microscopy, we show that in the presence of negatively charged membranes, proIAPP exhibits a much higher amyloidogenic propensity than in bulk solvent. Compared to hIAPP, it is still much less amyloidogenic, however. Although differences in the secondary structures of the aggregated species of hIAPP and proIAPP at the lipid interface are small, they are reflected in morphological changes. Unlike hIAPP, proIAPP forms essentially oligomeric-like structures at the lipid interface. Besides the interaction with anionic membranes [1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)+x1,2-dioleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)]], interaction with zwitterionic homogeneous (DOPC) and heterogeneous (1,2-dipalmitoyl-sn-glycero-3-phosphocholine:DOPC:cholesterol 1:2:1 model raft mixture) membranes has also been studied. Both peptides do not aggregate significantly at DOPC bilayers. In the presence of the model raft membrane, hIAPP aggregates markedly as well. Conversely, proIAPP clusters into less ordered structures and to a minor extent at raft membranes only. The addition of proIAPP to hIAPP retards the hIAPP fibrillation process also in the presence of negatively charged lipid bilayers. In excess proIAPP, increased aggregation levels are finally observed, however, which could be attributed to seed-induced cofibrillation of proIAPP.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1089-8638
pubmed:author
pubmed:issnType
Electronic
pubmed:day
26
pubmed:volume
389
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
907-20
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Amyloidogenic propensities and conformational properties of ProIAPP and IAPP in the presence of lipid bilayer membranes.
pubmed:affiliation
Department of Chemistry, TU Dortmund University, Germany.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't