Stem-loop

<p>Stem-loops are <a href="/facts/Nucleic_acid/2tTgcI0v">nucleic acid</a> <a href="/facts/Biomolecular_structure/VaN6MEYh">secondary structural</a> elements which form via intramolecular <a href="/facts/Base_pair/xmPpPQ9W">base pairing</a> in single-stranded <a href="/facts/DNA/nB89Iauz">DNA</a> or <a href="/facts/RNA/HxPeNfNj">RNA</a>. They are also referred to as hairpins or hairpin loops. A stem-loop occurs when two regions of the same nucleic acid strand, usually <a href="/facts/Complementarity_(molecular_biology)/WQfqGlBJ">complementary</a> in <a href="/facts/Nucleotide/pQKEwlJI">nucleotide</a> sequence, base-pair to form a double helix that ends in a loop of unpaired nucleotides. 
</p><p>Stem-loops are most commonly found in RNA, and are a key building block of many RNA <a href="/facts/Biomolecular_structure/VaN6MEYh">secondary structures</a>. Stem-loops can direct RNA folding, protect structural stability for <a href="/facts/Messenger_RNA/oUL6qxQn">messenger RNA</a> (mRNA), provide recognition sites for <a href="/facts/RNA-binding_protein/qTPTczLC">RNA binding proteins</a>, and serve as a <a href="/facts/Substrate_(chemistry)/6MnaV19h">substrate</a> for <a href="/facts/Enzyme_catalysis/4a283vgL">enzymatic reactions</a>.
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Stem-loop open-in-new

Stem-loop