biology

Protein-glutamate methylesterase

Protein-glutamate methylesterase 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 Protein-glutamate methylesterase rather than just read about it. In short: The enzyme protein-glutamate methylesterase (EC 3.1.1.61) catalyzes the reaction protein L-glutamate O 5-methyl ester + H2O ⇌ {\displaystyle \rightleftharpoons } protein L-glutamate + methanol This enzyme is a demethylase, and more specifically it belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name is protein-Lglutamate-O 5-methyl-ester acylhydrolase.

Key takeaways

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Reference excerpt

The enzyme protein-glutamate methylesterase (EC 3.1.1.61) catalyzes the reaction

protein L-glutamate O 5-methyl ester + H2O ⇌ {\displaystyle \rightleftharpoons } protein L-glutamate + methanol This enzyme is a demethylase, and more specifically it belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name is protein-Lglutamate-O 5-methyl-ester acylhydrolase. Other names in common use include chemotaxis-specific methylesterase, methyl-accepting chemotaxis protein methyl-esterase, CheB methylesterase, methylesterase CheB, protein methyl-esterase, protein carboxyl methylesterase, PME, protein methylesterase, and protein-L-glutamate-5-O-methyl-ester acylhydrolase. This enzyme participates in 3 metabolic pathways: two-component system - general, bacterial chemotaxis - general, and bacterial chemotaxis - organism-specific. CheB is part of a two-component signal transduction system. These systems enable bacteria to sense, respond, and adapt to a wide range of environments, stressors, and growth conditions. Two-component systems are composed of a sensor histidine kinase (HK) and its cognate response regulator (RR). The HK catalyses its own autophosphorylation followed by the transfer of the phosphoryl group to the receiver domain on RR; phosphorylation of the RR usually activates an attached output domain, in this case a methyltransferase domain. CheB is involved in chemotaxis. CheB methylesterase is responsible for removing the methyl group from the gamma-glutamyl methyl ester residues in the methyl-accepting chemotaxis proteins (MCP). CheB is regulated through phosphorylation by CheA. The N-terminal region of the protein is similar to that of other regulatory components of sensory transduction systems.

Structural studies As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes PDB: 1A2O and PDB: 1CHD.

References

Further reading Kehry MR, Doak TG, Dahlquist FW (1984). "Stimulus-induced changes in methylesterase activity during chemotaxis in Escherichia coli". J. Biol. Chem. 259 (19): 11828–35. doi:10.1016/S0021-9258(20)71286-X. PMID 6384215.

Illustrations

Worked examples

Example 1 — a first encounter with Protein-glutamate methylesterase

Start with the simplest possible case. Write down what Protein-glutamate methylesterase 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 Protein-glutamate methylesterase 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 Protein-glutamate methylesterase 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 Protein-glutamate methylesterase

In research: Protein-glutamate methylesterase 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 Protein-glutamate methylesterase 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: Protein-glutamate methylesterase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 3.1.1, EC 3.1 stubs, Enzymes of known structure, so understanding it makes those chapters shorter.
In everyday life: Look for Protein-glutamate methylesterase 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 Protein-glutamate methylesterase in simple terms?

The enzyme protein-glutamate methylesterase (EC 3.1.1.61) catalyzes the reaction protein L-glutamate O 5-methyl ester + H2O ⇌ {\displaystyle \rightleftharpoons } protein L-glutamate + methanol This enzyme is a demethylase, and more specifically it belongs to the family of hydrolases, specifically t…

Why does Protein-glutamate methylesterase 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 Protein-glutamate methylesterase?

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 Protein-glutamate methylesterase.