biology

Small multidrug resistance protein

Small multidrug resistance protein 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 Small multidrug resistance protein rather than just read about it. In short: Small multidrug resistance proteins (also known as drug/metabolite transporter) are a family of integral membrane proteins that confer drug resistance to a wide range of toxic compounds including guanidinium, hydrophobic drugs, antiseptics, polyamines, and glycolipids, by removing them for the cells. Within the family there are four subtypes.

Key takeaways

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

Reference excerpt

Small multidrug resistance proteins (also known as drug/metabolite transporter) are a family of integral membrane proteins that confer drug resistance to a wide range of toxic compounds including guanidinium, hydrophobic drugs, antiseptics, polyamines, and glycolipids, by removing them for the cells. Within the family there are four subtypes. Small multidrug resistance proteins are characterized by four α-helical transmembrane strands. SMR proteins are some of the smallest membrane transport proteins found in nature. The efflux is coupled to an influx of protons. An example is Escherichia coli mvrC P23895 which prevents the incorporation of methyl viologen into cells and is involved in ethidium bromide efflux. The four functional subtypes of small multidrug resistance proteins make up approximately 97% of small multidrug resistant proteins. One subtype, called GDx (Guanidinium export) transports guanidinium, which is a byproduct of the nitrogen metabolic process. The subtype Qac (Quaternary Ammonium Cation) exports hydrophobic cationic compounds. These two subtypes are relevant because they have been shown to aid in resistance to antiseptics used in human households. Another subtype (mdtI/mdtJ), is named for the genes mdtI/mdtJ, is associated with the transport of small polyamine metabolites. The subtype arnE/arnF, named for the genes arnE/arnF, transports glycolipids. Co-expressed genes can make up "paired SMRs" in all four functional subtypes. It is predicted that these paired SMRs developed through many independent duplications. The genes that encode small multidrug resistance proteins are often found in the assessment of profiles with drug resistance. Their dual topology gives them the unique advantage to insert into a membrane in either inward or outward positions. Antimicrobials are being developed to target small multidrug resistance proteins because of the role of SMR proteins in resistance to treatment and management.

References

Worked examples

Example 1 — a first encounter with Small multidrug resistance protein

Start with the simplest possible case. Write down what Small multidrug resistance protein 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 Small multidrug resistance protein 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 Small multidrug resistance protein 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 Small multidrug resistance protein

In research: Small multidrug resistance protein 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 Small multidrug resistance protein 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: Small multidrug resistance protein is common in secondary-school and first-year university syllabi. It links to neighbouring topics Membrane protein stubs, Membrane proteins, Protein domains, so understanding it makes those chapters shorter.
In everyday life: Look for Small multidrug resistance protein 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 Small multidrug resistance protein in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Small multidrug resistance protein 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 Small multidrug resistance protein out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Small multidrug resistance protein in simple terms?

Why does Small multidrug resistance protein 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 Small multidrug resistance protein?

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 Small multidrug resistance protein.