Human Islet Amyloid Polypeptide Assembly: The Key Role of the 8-20 Fragment.
J Phys Chem B
; 120(46): 11905-11911, 2016 11 23.
Article
em En
| MEDLINE
| ID: mdl-27785911
ABSTRACT
The aggregation of human islet amyloid polypeptide (hIAPP) has been closely associated with the pathogeny of type 2 diabetes mellitus (T2DM) and destruction of pancreatic islet ß-cells. Several amyloidogenic domains within the hIAPP sequence capable of self-association have been identified. Among them is the 8-20 region of hIAPP, which has formed ß-sheet fibrils despite being contained within an α-helical region of full-length hIAPP. To further understand the propensity of this region for self-assembly, two peptide fragments were compared, one consisting of the residues 8-20 (WT8-20) and a mutant fragment with a His18Pro substitution (H18P8-20). The conformational distribution and aggregation propensity of these peptides was determined using a combination of ion mobility mass spectrometry and atomic force microscopy. Our results reveal that the two peptide fragments have vastly differing assembly pathways. WT8-20 produces a wide range of oligomers up to decamer whereas the H18P8-20 mutant produces only low order oligomers. This study confirms the propensity of the 8-20 region to aggregate from its native α-helical structure into amyloid ß-sheet oligomers and highlights the significance of the charged His18 in the aggregation process.
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Base de dados:
MEDLINE
Assunto principal:
Fragmentos de Peptídeos
/
Polipeptídeo Amiloide das Ilhotas Pancreáticas
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article