Complex conformational dynamics of the heart failure‐associated pre‐mirna‐377 hairpin revealed by single‐molecule optical tweezers

• pre‐miRNA‐377 is a hairpin‐shaped regulatory RNA associated with heart failure. Here, we use single‐molecule optical tweezers to unzip pre‐miRNA‐377 and study its stability and dy-namics. We show that magnesium ions have a strong stabilizing effect, and that sodium ions stabi-lize the hairpin more than potassium ions. The hairpin unfolds in a single step, regardless of buffer composition. Interestingly, hairpin folding occurs either in a single step (type 1) or through the formation of intermediates, in multiple steps (type 2) or gradually (type 3). Type 3 occurs only in the presence of both sodium and magnesium, while type 1 and 2 take place in all buffers, with type 1 being the most prevalent. By reducing the size of the native hairpin loop from fourteen to four nu-cleotides, we demonstrate that the folding heterogeneity originates from the large size of the hairpin loop. Further, while efficient pre‐miRNA‐377 binders are lacking, we demonstrate that the recently developed C2 ligand displays bimodal activity: it enhances the mechanical stability of the pre-miRNA‐377 hairpin and perturbs its folding. The knowledge regarding pre‐miRNA stability and dynamics that we provide is important in understanding its regulatory function and how it can be modulated to achieve a therapeutic effect, e.g., in heart failure treatment.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

NATURVETENSKAP  -- Biologi -- Biofysik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biophysics (hsv//eng)

Nyckelord

RNA folding het-erogeneity

Pre‐miRNA

RNA‐ligand interaction

RNA dynamics

Optical tweezers

Pre‐miRNA‐377

MiRNA

Single‐molecule force spectroscopy

Heart failure

Publikations- och innehållstyp

art (ämneskategori)

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