Equilibria and kinetics of folding of gelsolin domain 2 and mutants involved in familial amyloidosis-Finnish type.


Abstract

Mutations D187N and D187Y in domain 2 of the actin-regulating protein gelsolin cause familial amyloidosis-Finnish type (FAF). We have constructed and expressed a recombinant version of gelsolin domain 2 that is sufficiently stable for kinetic and equilibrium measurements. The wild-type domain and the two amyloidogenic mutants fold via simple two-state kinetics without the accumulation of an intermediate. Unfolding kinetics exhibits significant curvature with increasing urea concentration, indicating that the transition state for unfolding becomes more native-like under increasingly denaturing conditions in accordance with the Hammond postulate. Mutations D187N and D187Y destabilize gelsolin domain 2 by 1.22 and 2.16 kcal. mol(-1) (1 kcal = 4.18 kJ) respectively. The mutations do not prevent disulfide bond formation despite their direct contiguity with a cysteine residue involved in disulfide linkage. The destabilization conferred on gelsolin domain 2 by the FAF mutations is sufficient to predict that an appreciable fraction is unfolded and, therefore, extremely susceptible to proteolysis at body temperature. Study holds ProTherm entries: 6490, 6491, 6492, 6493 Extra Details: protein; stability; denaturation; Hammond; two-state

Submission Details

ID: ezWdA95J

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:32 p.m.

Version: 1

Publication Details
Isaacson RL;Weeds AG;Fersht AR,Proc. Natl. Acad. Sci. U.S.A. (1999) Equilibria and kinetics of folding of gelsolin domain 2 and mutants involved in familial amyloidosis-Finnish type. PMID:10500162
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