biology

P-Aminobenzoyl-glutamate transporter

P-Aminobenzoyl-glutamate transporter 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 P-Aminobenzoyl-glutamate transporter rather than just read about it. In short: The p-aminobenzoyl-glutamate transporter (AbgT) family (TC# 2.A.68) is a family of transporter proteins belonging to the ion transporter (IT) superfamily. The AbgT family consists of the AbgT (YdaH; TC# 2.A.68.1.1) protein of E. coli and the MtrF drug exporter (TC# 2.A.68.1.2) of Neisseria gonorrhoeae.

Key takeaways

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

Reference excerpt

The p-aminobenzoyl-glutamate transporter (AbgT) family (TC# 2.A.68) is a family of transporter proteins belonging to the ion transporter (IT) superfamily. The AbgT family consists of the AbgT (YdaH; TC# 2.A.68.1.1) protein of E. coli and the MtrF drug exporter (TC# 2.A.68.1.2) of Neisseria gonorrhoeae. The former protein is apparently cryptic in wild-type cells, but when expressed on a high copy number plasmid, or when expressed at higher levels due to mutation, it appeared to allow uptake (Km = 123 nM; see Michaelis–Menten kinetics) and subsequent utilization of p-aminobenzoyl-glutamate as a source of p-aminobenzoate for p-aminobenzoate auxotrophs. p-Aminobenzoate is a constituent of and a precursor for the biosynthesis of folic acid. MtrF was annotated as a putative drug efflux pump.

Structure AbgT is 510 amino acyl residues long and has 12-13 putative transmembrane α-helical spanners (TMSs). MtrF is 522 aas long and has 11 or 12 putative TMSs. The 3-d structures of MtrF and a YdaH homologue have been solved, and functional studies show that it is a drug exporter. The 3-d structure shows that it has 9 TMSs with hairpin entry loops. Crystal Structures:

Genetics The abgT gene is preceded by two genes, abgA and abgB, which code for homologous amino acyl amino hydrolases and hydrolyze p-aminobenzoyl glutamate to p-aminobenzoate and glutamate. Because of the structural similarity of p-aminobenzoyl-glutatmate to peptides, and the enzymatic activities of the abgA and abgB gene products, it has been suggested that AbgT is also a peptide transporter. Demonstration of an energy requirement suggested an H+-dependent mechanism. Expression of these genes is regulated by AbgR and an unknown effector.

Function As noted above, the AbgT family of transporters has been thought to contribute to bacterial folate biosynthesis by importing the catabolite p-aminobenzoyl-glutamate for producing folate. Approximately 13,000 putative family members were identified in 2015. The X-ray structures of the full-length Alcanivorax borkumensis YdaH (AbgT) and Neisseria gonorrhoeae MtrF proteins. The structures revealed that these two transporters assemble as dimers with architectures distinct from all other families of transporters for which 3-d structures were available. Both YdaH and MtrF are bowl-shaped dimers with a solvent-filled basin extending from the cytoplasm halfway across the membrane bilayer. The protomers of YdaH and MtrF contain nine transmembrane helices and two hairpins which suggested a plausible pathway for substrate transport. A combination of the crystal structure, genetic analyses and substrate accumulation assays indicated that both YdaH and MtrF behave as exporters, capable of removing the folate metabolite p-aminobenzoic acid from bacterial cells. In fact, it was shown that both YdaH and MtrF participate as antibiotic efflux pumps, mediating bacterial resistance to sulfonamide antimetabolite drugs. Possibly, many AbgT-family transporters act as exporters, conferring resistance to sulfonamides.

Transport reaction The generalized transport reaction initially proposed for AbgT is:p-aminobenzoyl-glutamate (out) + nH+ (out) → p-aminobenzoyl-glutamate (in) + nH+ (in)but the more recently proposed transport reaction is:Sulfonamide drugs (in) + H+ (out) → Sulfonamide drugs (out) + H+ (in)

See also Antimicrobial resistance Membrane transport protein Transporter Classification Database

References

Worked examples

Example 1 — a first encounter with P-Aminobenzoyl-glutamate transporter

Start with the simplest possible case. Write down what P-Aminobenzoyl-glutamate transporter 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 P-Aminobenzoyl-glutamate transporter 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 P-Aminobenzoyl-glutamate transporter 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 P-Aminobenzoyl-glutamate transporter

In research: P-Aminobenzoyl-glutamate transporter 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 P-Aminobenzoyl-glutamate transporter 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: P-Aminobenzoyl-glutamate transporter is common in secondary-school and first-year university syllabi. It links to neighbouring topics Integral membrane proteins, Membrane proteins, Protein families, so understanding it makes those chapters shorter.
In everyday life: Look for P-Aminobenzoyl-glutamate transporter 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 P-Aminobenzoyl-glutamate transporter in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what P-Aminobenzoyl-glutamate transporter 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 P-Aminobenzoyl-glutamate transporter out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is P-Aminobenzoyl-glutamate transporter in simple terms?

Why does P-Aminobenzoyl-glutamate transporter 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 P-Aminobenzoyl-glutamate transporter?

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 P-Aminobenzoyl-glutamate transporter.