Elucidating the mechanism of familial amyloidosis-Finnish type: NMR studies of human gelsolin domain 2

Steven L. Kazmirski, Mark J. Howard, Rivka L. Isaacson, Alan R. Fersht*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

Familial amyloidosis-Finnish type (FAF) results from a single mutation at residue 187 (D187N or D187Y) within domain 2 of the actin-regulating protein gelsolin. The mutation somehow allows a masked cleavage site to be exposed, leading to the first step in the formation of an amyloidogenic fragment. We have performed NMR experiments investigating structural and dynamic changes between wild-type (WT) and D187N gelsolin domain 2 (D2). On mutation, no significant structural or dynamic changes occur at or near the cleavage site. Areas in conformational exchange are observed between β-strand 4 and α-helix 1 and within the loop region following β-strand 5. Chemical shift differences are noted along the face of α-helix 1 that packs onto the β-sheet, suggesting an altered conformation. Conformational changes within these areas can have an effect on actin binding and may explain why D187N gelsolin is inactive. {1H-15N} nuclear Overhauser effect and chemical shift data suggest that the C-terminal tail of D187N gelsolin D2 is less structured than WT by up to six residues. In the crystal structure of equine gelsolin, the C-terminal tail of D2 lies across a large cleft between domains 1 and 2 where the masked cleavage site sits. We propose that the D187N mutation destabilizes the C-terminal tail of D2 resulting in a more exposed cleavage site leading to the first proteolysis step in the formation of the amyloidogenic fragment.

Original languageEnglish
Pages (from-to)10706-10711
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume97
Issue number20
DOIs
Publication statusPublished - 26 Sept 2000

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