biology

Phenylalanine–tRNA ligase

Phenylalanine–tRNA ligase is a biology 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 Phenylalanine–tRNA ligase rather than just read about it. In short: In enzymology, a phenylalanine–tRNA ligase (EC 6.1.1.20) is an enzyme that catalyzes the chemical reaction ATP + L-phenylalanine + tRNAPhe ⇌ {\displaystyle \rightleftharpoons } AMP + diphosphate + L-phenylalanyl-tRNAPhe The 3 substrates of this enzyme are ATP, L-phenylalanine, and tRNAPhe, whereas its 3 products are AMP, diphosphate, and L-phenylalanyl-tRNAPhe. This enzyme belongs to the family of ligases, to be spe…

Key takeaways

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

Reference excerpt

In enzymology, a phenylalanine–tRNA ligase (EC 6.1.1.20) is an enzyme that catalyzes the chemical reaction

ATP + L-phenylalanine + tRNAPhe ⇌ {\displaystyle \rightleftharpoons } AMP + diphosphate + L-phenylalanyl-tRNAPhe The 3 substrates of this enzyme are ATP, L-phenylalanine, and tRNAPhe, whereas its 3 products are AMP, diphosphate, and L-phenylalanyl-tRNAPhe. This enzyme belongs to the family of ligases, to be specific those forming carbon–oxygen bonds in aminoacyl-tRNA and related compounds. The systematic name of this enzyme class is L-phenylalanine:tRNAPhe ligase (AMP-forming). Other names in common use include phenylalanyl-tRNA synthetase, phenylalanyl-transfer ribonucleate synthetase, phenylalanine-tRNA synthetase, phenylalanyl-transfer RNA synthetase, phenylalanyl-tRNA ligase, phenylalanyl-transfer RNA ligase, L-phenylalanyl-tRNA synthetase, and phenylalanine translase. This enzyme participates in phenylalanine, tyrosine and tryptophan biosynthesis and aminoacyl-tRNA biosynthesis. Phenylalanine-tRNA synthetase (PheRS) is known to be among the most complex enzymes of the aaRS (aminoacyl-tRNA synthetase) family. Bacterial and mitochondrial PheRSs share a ferredoxin-fold anticodon binding (FDX-ACB) domain, which represents a canonical double split alpha+beta motif having no insertions. The FDX-ACB domain displays a typical RNA recognition fold (RRM) formed by the four-stranded antiparallel beta sheet, with two helices packed against it.

Structural studies As of late 2007, 10 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1B70, PDB: 1B7Y, PDB: 1EIY, PDB: 1JJC, PDB: 1PYS, PDB: 2AKW, PDB: 2ALY, PDB: 2AMC, PDB: 2CXI, and PDB: 2IY5.

References

Further reading Stulberg MP (1967). "The isolation and properties of phenylalanyl ribonucleic acid synthetase from Escherichia coli B". J. Biol. Chem. 242 (5): 1060–4. doi:10.1016/S0021-9258(18)96232-0. PMID 5335910.

Illustrations

Worked examples

Example 1 — a first encounter with Phenylalanine–tRNA ligase

Start with the simplest possible case. Write down what Phenylalanine–tRNA ligase claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Phenylalanine–tRNA ligase 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 Phenylalanine–tRNA ligase 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 Phenylalanine–tRNA ligase

In research: Phenylalanine–tRNA ligase appears in biology 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 Phenylalanine–tRNA ligase 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: Phenylalanine–tRNA ligase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 6.1.1, Enzymes of known structure, Ligase stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Phenylalanine–tRNA ligase 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 Phenylalanine–tRNA ligase in 20 minutes

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Frequently asked questions

What is Phenylalanine–tRNA ligase in simple terms?

In enzymology, a phenylalanine–tRNA ligase (EC 6.1.1.20) is an enzyme that catalyzes the chemical reaction ATP + L-phenylalanine + tRNAPhe ⇌ {\displaystyle \rightleftharpoons } AMP + diphosphate + L-phenylalanyl-tRNAPhe The 3 substrates of this enzyme are ATP, L-phenylalanine, and tRNAPhe, whereas…

Why does Phenylalanine–tRNA ligase matter?

Because it connects several biology 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 Phenylalanine–tRNA ligase?

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 Phenylalanine–tRNA ligase.