Structural mapping of an aggregation nucleation site in a molten globule intermediate.
Protein aggregation plays an important role in biotechnology and also causes numerous diseases. Human carbonic anhydrase II is a suitable model protein for studying the mechanism of aggregation. We found that a molten globule state of the enzyme formed aggregates. The intermolecular interactions involved in aggregate formation were localized in a direct way by measuring excimer formation between each of 20 site-specific pyrene-labeled cysteine mutants. The contact area of the aggregated protein was very specific, and all sites included in the intermolecular interactions were located in the large beta-sheet of the protein, within a limited region between the central beta-strands 4 and 7. This substructure is very hydrophobic, which underlines the importance of hydrophobic interactions between specific beta-sheet containing regions in aggregate formation.
Hammarström
P
P
Department of Physics Measurement Technology, Linköping University, SE-581 83 Linköping, Sweden.
Persson
M
M
Freskgârd
P O
PO
Mârtensson
L G
LG
Andersson
D
D
Jonsson
B H
BH
Carlsson
U
U
D002256:Carbonic Anhydrases / Q000737:chemistry* / Q000235:genetics; D018834:Chaperonin 60 / Q000378:metabolism; D003545:Cysteine / Q000235:genetics; D005456:Fluorescent Dyes; D006801:Humans; D008301:Maleimides / Q000737:chemistry; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry
D018834:Chaperonin 60; D005456:Fluorescent Dyes; D008301:Maleimides; D014364:Tryptophan; C003944:N-(3-pyrene)maleimide; D002256:Carbonic Anhydrases; D003545:Cysteine