Disulfide bond formation
is fundamentally important for protein
structure and constitutes a key mechanism by which cells regulate
the intracellular oxidation state. Peroxiredoxins (PRDXs) eliminate
reactive oxygen species such as hydrogen peroxide through a catalytic
cycle of Cys oxidation and reduction. Additionally, upon Cys oxidation
PRDXs undergo extensive conformational rearrangements that may underlie
their presently structurally poorly defined functions as molecular
chaperones. Rearrangements include high molecular-weight oligomerization,
the dynamics of which are, however, poorly understood, as is the impact
of disulfide bond formation on these properties. Here we show that
formation of disulfide bonds along the catalytic cycle induces extensive
μs time scale dynamics, as monitored by magic-angle spinning
NMR of the 216 kDa-large Tsa1 decameric assembly and solution-NMR
of a designed dimeric mutant. We ascribe the conformational dynamics
to structural frustration, resulting from conflicts between the disulfide-constrained
reduction of mobility and the desire to fulfill other favorable contacts.