engineering

Polynucleotide adenylyltransferase

Polynucleotide adenylyltransferase is a engineering 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 Polynucleotide adenylyltransferase rather than just read about it. In short: In enzymology, a polynucleotide adenylyltransferase (EC 2.7.7.19) is an enzyme that catalyzes the chemical reaction ATP + RNA-3'OH ⇌ {\displaystyle \rightleftharpoons } pyrophosphate + RNApA-3'OH Thus, the two substrates of this enzyme are ATP and RNA, whereas its two products are pyrophosphate and RNA with an extra adenosine nucleotide at its 3' end. Human genes with this activity include TUT1, MTPAP, PAPOLA, PAPOL…

Key takeaways

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Reference excerpt

In enzymology, a polynucleotide adenylyltransferase (EC 2.7.7.19) is an enzyme that catalyzes the chemical reaction

ATP + RNA-3'OH ⇌ {\displaystyle \rightleftharpoons } pyrophosphate + RNApA-3'OH

Thus, the two substrates of this enzyme are ATP and RNA, whereas its two products are pyrophosphate and RNA with an extra adenosine nucleotide at its 3' end. Human genes with this activity include TUT1, MTPAP, PAPOLA, PAPOLB, PAPOLG, TENT2, TENT4A, TENT4B, TENT5C, TENT5D.

Function This enzyme is responsible for the addition of the 3' polyadenine tail to a newly synthesized pre-messenger RNA (pre-mRNA) molecule during the process of gene transcription. The protein is the final addition to a large protein complex that also contains smaller assemblies known as the cleavage and polyadenylation specificity factor (CPSF) and cleavage stimulatory factor (CtSF) and its binding is a necessary prerequisite to the cleavage of the 3' end of the pre-mRNA. After cleavage of the 3' signaling region that directs the assembly of the complex, polyadenylate polymerase (PAP) adds the polyadenine tail to the new 3' end. The rate at which PAP adds adenine nucleotides is dependent on the presence of another regulatory protein, PABPII (poly-adenine binding protein II). The first few nucleotides added by PAP are added very slowly, but the short polyadenine tail is then bound by PABPII, which accelerates the rate of adenine addition by PAP. The final tail is about 200-250 adenine nucleotides long in mammals. PAP is phosphorylated by mitosis-promoting factor, a key regulator of the cell cycle. High phosphorylation levels decrease PAP activity.

Structural studies As of late 2007, 27 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1AV6, PDB: 1B42, PDB: 1BKY, PDB: 1EAM, PDB: 1EQA, PDB: 1F5A, PDB: 1FA0, PDB: 1JSZ, PDB: 1JTE, PDB: 1JTF, PDB: 1P39, PDB: 1Q78, PDB: 1Q79, PDB: 1V39, PDB: 1VFG, PDB: 1VP3, PDB: 1VP9, PDB: 1VPT, PDB: 2GA9, PDB: 2GAF, PDB: 2HHP, PDB: 2O1P, PDB: 2Q66, PDB: 2VP3, PDB: 3MAG, PDB: 3MCT, and PDB: 4DCG.

References

Illustrations

Worked examples

Example 1 — a first encounter with Polynucleotide adenylyltransferase

Start with the simplest possible case. Write down what Polynucleotide adenylyltransferase claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, 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 Polynucleotide adenylyltransferase 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 Polynucleotide adenylyltransferase 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 Polynucleotide adenylyltransferase

In research: Polynucleotide adenylyltransferase appears in engineering 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 Polynucleotide adenylyltransferase 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: Polynucleotide adenylyltransferase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 2.7.7, Enzymes of known structure, so understanding it makes those chapters shorter.
In everyday life: Look for Polynucleotide adenylyltransferase 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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Frequently asked questions

What is Polynucleotide adenylyltransferase in simple terms?

In enzymology, a polynucleotide adenylyltransferase (EC 2.7.7.19) is an enzyme that catalyzes the chemical reaction ATP + RNA-3'OH ⇌ {\displaystyle \rightleftharpoons } pyrophosphate + RNApA-3'OH Thus, the two substrates of this enzyme are ATP and RNA, whereas its two products are pyrophosphate and…

Why does Polynucleotide adenylyltransferase matter?

Because it connects several engineering 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 Polynucleotide adenylyltransferase?

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 Polynucleotide adenylyltransferase.