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Lysine riboswitch

Lysine riboswitch is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lysine riboswitch rather than just read about it. In short: The Lysine riboswitch is a metabolite binding RNA element found within certain messenger RNAs that serve as a precision sensor for the amino acid lysine. Allosteric rearrangement of mRNA structure is mediated by ligand binding, and this results in modulation of gene expression.

Lysine riboswitch — main illustration
Lysine riboswitch — illustration

Key takeaways

  • Lysine riboswitch belongs to chemistry; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Lysine riboswitch to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Lysine riboswitch from memory before moving on to harder problems.

Reference excerpt

The Lysine riboswitch is a metabolite binding RNA element found within certain messenger RNAs that serve as a precision sensor for the amino acid lysine. Allosteric rearrangement of mRNA structure is mediated by ligand binding, and this results in modulation of gene expression. Lysine riboswitch are most abundant in Bacillota and Gammaproteobacteria where they are found upstream of a number of genes involved in lysine biosynthesis, transport and catabolism. The lysine riboswitch has also been identified independently and called the L box. The lysine riboswitch controls metabolic pathways of lysine biosynthesis. In particular the metabolic flux of the tricarboxylic acid (TCA) cycle is effectively controlled by the riboswitch. Controlling metabolic flux is imperative for the development of microorganisms in cell growth, and the use of the lysine riboswitch in its applicable bacterium allows for the use of more effective strategies to accomplish control. It is more effective in comparison to various expensive and difficult methods such as utilizing a gene knockout. With lysine as an intracellular signal, the riboswitch regulates gene expression in response to specific metabolites. The lysine riboswitch was first investigated in Bacilus subtilis, located at the 5'UTR of the lysC gene coding for aspartokinase. It has since been found in E. coli (ECRS) with the ability to inhibit translation of aspartokinase III in E. coli and accelerate mRNA decay. In both E. coli and Bacilus subtilis, the lysine riboswitch controls the production of citrate synthase, and therefore metabolic flux in the TCA cycle as decreases in citrate synthase activity contributes to increases in lysine production. Control of TCA cycle activity thus affects the biosynthesis of lysine indicating a higher metabolic flux into the lysine synthesis pathway.It has no inhibitory effect on transcription except for in Bacilus subtilis. The ligand binding domain of the riboswitch binds to L Lysine.

Structure The structure of the lysine riboswitch has recently been determined. The lysine amino acid is bound in the pocket formed by the 5-way junction. The structure is composed of a three helical bundle and a two helical bundle joined by the 5-way junction. Helices 1 and 2 are stacked in a colinear fashion as are helices 4 and 5.

See also Glycine riboswitch Glutamine riboswitch

References

External links

Page for Lysine riboswitch at Rfam PDB entry for the lysine riboswitch tertiary structure

Illustrations

Lysine riboswitch illustration
Lysine riboswitch: The binding pocket of L-lysine as depicted by the lysine attachment to the lysine riboswitch.
The binding pocket of L-lysine as depicted by the lysine attachment to the lysine riboswitch.
Lysine riboswitch illustration

Worked examples

Example 1 — a first encounter with Lysine riboswitch

Start with the simplest possible case. Write down what Lysine riboswitch claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lysine riboswitch before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lysine riboswitch ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lysine riboswitch

In research
Lysine riboswitch appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Lysine riboswitch in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Lysine riboswitch is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cis-regulatory RNA elements, Molecular and cellular biology stubs, Riboswitch, so understanding it makes those chapters shorter.
In everyday life
Look for Lysine riboswitch outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Lysine riboswitch in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Lysine riboswitch means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Lysine riboswitch out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lysine riboswitch in simple terms?

The Lysine riboswitch is a metabolite binding RNA element found within certain messenger RNAs that serve as a precision sensor for the amino acid lysine. Allosteric rearrangement of mRNA structure is mediated by ligand binding, and this results in modulation of gene expression.

Why does Lysine riboswitch matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lysine riboswitch?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lysine riboswitch.

Tags

  • Cis-regulatory RNA elements
  • Molecular and cellular biology stubs
  • Riboswitch

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