chemistry

Lanthionine

Lanthionine 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 Lanthionine rather than just read about it. In short: Lanthionine is a nonproteinogenic amino acid with the chemical formula (HOOC-CH(NH2)-CH2-S-CH2-CH(NH2)-COOH). It is typically formed by a cysteine residue and a dehydrated serine residue.

Key takeaways

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

Reference excerpt

Lanthionine is a nonproteinogenic amino acid with the chemical formula (HOOC-CH(NH2)-CH2-S-CH2-CH(NH2)-COOH). It is typically formed by a cysteine residue and a dehydrated serine residue. Despite its name, lanthionine does not contain the element lanthanum.

Background In 1941, lanthionine was first isolated by treating wool with sodium carbonate. It was found to be a sulfur-containing amino acid; accordingly it was given the name lanthionine [wool (Latin: Lana), sulfur (Greek: theîon)]. Lanthionine was first synthesized by alkylation of cysteine with β-chloroalanine. Lanthionines are found widely in nature. They have been isolated from human hair, lactalbumin, and feathers. Lanthionines have also been found in bacterial cell walls and are the components of a group of gene-encoded peptide antibiotics called lantibiotics, which includes nisin (a food preservative), subtilin, epidermin (effective against Staphylococcus and Streptococcus), and ancovenin (an enzyme inhibitor). Lanthionine is listed among novel uremic toxins, compounds elevated in blood of chronic kidney failure and uremic patiens. It likely contributes to hyperhomocysteinemia and impaired hydrogen sulfide biosynthesis. Lanthionine retention may also be linked to adverse cardiovascular outcomes as it can induce heart tissue fibrosis and promote vascular calcification.

Preparation A variety of syntheses of lanthionine have been published including sulfur extrusion from cystine, ring opening of serine β-lactone, and hetero-conjugate addition of cysteine to dehydroalanine. The sulfur extrusion method is, however, the only pathway for lanthionine that has been employed in the total synthesis of a lantibiotic. Biosynthesis of the lanthionine bridge in peptidic natural products can be accomplished through a number of different pathways. For example, the lanthionine bridges in the antibiotic nisin are the result of a dedicated dehydratase (NisB) and a dedicated cyclase (NisC).

References

Illustrations

Worked examples

Example 1 — a first encounter with Lanthionine

Start with the simplest possible case. Write down what Lanthionine 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 Lanthionine 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 Lanthionine 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 Lanthionine

In research: Lanthionine 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 Lanthionine 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: Lanthionine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alpha-Amino acids, Non-proteinogenic amino acids, Sulfur amino acids, so understanding it makes those chapters shorter.
In everyday life: Look for Lanthionine 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 Lanthionine in 20 minutes

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

Frequently asked questions

What is Lanthionine in simple terms?

Lanthionine is a nonproteinogenic amino acid with the chemical formula (HOOC-CH(NH2)-CH2-S-CH2-CH(NH2)-COOH). It is typically formed by a cysteine residue and a dehydrated serine residue.

Why does Lanthionine 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 Lanthionine?

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 Lanthionine.