View source for Special sequences

<p>Certain structures in Eterna can only be solved using one or a few sequences.</p>
<h2>Zigzags</h2>
<p style="padding-left: 30px;"><em>Main article</em>: [[Zigzag]]</p>
<p>Zigzags have a large number of solutions, but they are not always immediately apparent and are unlikely to be found by random chance.</p>
<h2>Tricks Involving External Loops</h2>
<p>The [[External Loop|external loop]] can be thought of as a multiloop that lacks the quirks of the [[3-Branched Multiloop Puzzles|3-branched multiloop]].</p>
<h3>1-nt Bulge</h3>
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<td>The 1-nt bulge attached to an external loop requires one GC pair in the  orientation shown.  Whe the unpaired base is on the [[Directionality of  RNA|3' side]] of the bulge, as shown at right, the GU pair and unpaired  U are required. When the unpaired base is on the [[Directionality of  RNA|5' side]] of the bulge, an AU or GU pair will suffice.</td>
<td>[[File:SpecialSeq1.jpg|thumb|400px]]</td>
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<p></p>
<h3>2-1 Loop</h3>
<p>The 2-1 loop attached to an external loop or multiloop is best solved by the UU/U mismatch, but it can be done with a GG/A mismatch. It requires a GC solitary pair.</p>
<p><img title="aa" src="/wiki/images/1516183662.png" border="0" alt="aa" width="998" height="440" /></p>
<p>[[Category:Motif]][[Category:RNA]]</p>