In response to heat stress, all organisms — not just plants — alter their gene
expression, triggering the production of heat-shock proteins (HSPs). These
proteins help mediate protein folding and prevent unwanted aggregation within
the cell. Small HSPs are unusually complex and not well characterized in higher
plants. HSP21, one of these small HSPs specific to the chloroplast, is thought to
protect photosystem II (PSII), a protein complex readily destroyed by heat, from
both heat and oxidative stress within the cell.
To identify the precise role HSP21 plays in protecting PSII, researchers
conducted both biochemical and genetic analysis. To examine the
interaction between HSP21 and PSII more deeply, they used MST — a
biophysical method — to measure the binding affinity between HSP21 and
two protein subunits of PSII: D1 and D2, directly from cell lysates.
Taken together, their data provide the first direct evidence that HSP21 protects
PSII from heat stress, specifically by directly chaperoning its subunits. This
research lays the groundwork for a better understanding of how chloroplasts
stabilize photosynthetic complexes, particularly in the molecular context of heat
stress, and of how heat stress is regulated in plants.
Uncover how a chloroplast heat-shock
protein helps plants tolerate heat stress
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Molecular
interactions
studied
Target: Photosystem II
subunits D1 and D2
Ligand: HSP21
Method used
MST using Monolith
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