biology

Mabinlin

Mabinlin 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 Mabinlin rather than just read about it. In short: Mabinlins are sweet-tasting proteins extracted from the seed of mabinlang (Capparis masaikai Levl.), a plant growing in Yunnan province of China. There are four homologues.

Key takeaways

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

Reference excerpt

Mabinlins are sweet-tasting proteins extracted from the seed of mabinlang (Capparis masaikai Levl.), a plant growing in Yunnan province of China. There are four homologues. Mabinlin-2 was first isolated in 1983 and characterised in 1993, and is the most extensively studied of the four. The other variants of mabinlin-1, -3 and -4 were discovered and characterised in 1994.

Protein structures The 4 mabinlins are very similar in their amino acids sequences (see below).

Chain A M-1: EPLCRRQFQQ HQHLRACQRY IRRRAQRGGL VD M-2: QLWRCQRQFL QHQRLRACQR FIHRRAQFGG QPD M-3: EPLCRRQFQQ HQHLRACQRY LRRRAQRGGL AD M-4: EPLCRRQFQQ HQHLRACQRY LRRRAQRG Chain B M-1: EQRGPALRLC CNQLRQVNKP CVCPVLRQAA HQQLYQGQIE GPRQVRQLFR AARNLPNICK IPAVGRCQFT RW M-2: QPRRPALRQC CNQLRQVDRP CVCPVLRQAA QQVLQRQIIQ GPQQLRRLFD AARNLPNICN IPNIGACPFR AW M-3: EQRGPALRLC CNQLRQVNKP CVCPVLRQAA HQQLYQGQIE GPRQVRRLFR AARNLPNICK IPAVGRCQFT RW M-4: EQRGPALRLC CNQLRQVNKP CVCPVLRQAA HQQLYQGQIE GPRQVRRLFR AARNLPNICK IPAVGRCQFT RW Amino acid sequence of Mabinlins homologues are adapted from Swiss-Prot biological database of protein.

The molecular weights of Mabinlin-1, Mabinlin-3 and Mabinlin-4 are 12.3 kDa, 12.3 kDa and 11.9 kDa, respectively. With a molecular weight of 10.4kDa, mabinlin-2 is lighter than mabinlin-1. It is a heterodimer consisting of two different chains A and B produced by post-translational cleavage. The A chain is composed of 33 amino acid residues and the B chain is composed of 72 amino acid residues. The B chain contains two intramolecular disulfide bonds and is connected to the A chain through two intermolecular disulfide bridges. Mabinlin-2 is the sweet-tasting protein with the highest known thermostability, which is due to the presence of the four disulfide bridges. It has been suggested also that the difference in the heat stability of the different mabinlin homologues is due to the presence of an arginine residue (heat-stable homologue) or a glutamine (heat-unstable homologue) at position 47 in the B-chain. The B54-B64 segment of the beta chain in Mabinlin II is the primary functional domain that enables its function as a sweet protein.The segment contains the [NL/I] tetralit motif, a unique structural arrangement that contains four Asn-Leu/lle dipole units. The motif is stabilized by Pro56, Pro62, and a cysteine that is involved in a disulfide bridge, which includes CysB59-CysB11. The stabilization ensures a rigid and defined conformation.The region is one of the primary binding sites for receptor interaction such as the sweet receptor nTR2/T1R3. The sequences of Mabilins cluster with Napins (InterPro: IPR000617).

Sweetness properties Mabinlins sweetness were estimated to be about 100–400 times that of sucrose on molar basis, 10 times sucrose on a weight basis, which make them less sweet than thaumatin (3000 times) but elicit a similar sweetness profile. The sweetness of mabinlin-2 is unchanged after 48 hours incubation at 80 °C. Mabinlin-3 and -4 sweetness stayed unchanged after 1 hour at 80 °C, while mabinlin-1 loses sweetness after 1 hour at the same condition.

As a sweetener Mabinlins, as proteins, are readily soluble in water and found to be highly sweet; however, mabinlin-2 with its high heat stability has the best chance to be used as a sweetener. During the past decade, attempts have been made to produce mabinlin-2 industrially. The sweet-tasting protein has been successfully synthesised by a stepwise solid-phase method in 1998, however the synthetic protein had an astringent-sweet taste. Mabinlin-2 has been expressed in transgenic potato tubers, but no explicit results have been reported yet. However, patents to protect production of recombinant mabinlin by cloning and DNA sequencing have been issued.

See also Brazzein Monellin Pentadin Thaumatin

References

External links Media related to Mabinlin at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with Mabinlin

Start with the simplest possible case. Write down what Mabinlin 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 Mabinlin 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 Mabinlin 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 Mabinlin

In research: Mabinlin 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 Mabinlin 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: Mabinlin is common in secondary-school and first-year university syllabi. It links to neighbouring topics Proteins, Sugar substitutes, so understanding it makes those chapters shorter.
In everyday life: Look for Mabinlin 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 Mabinlin in 20 minutes

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

Frequently asked questions

What is Mabinlin in simple terms?

Mabinlins are sweet-tasting proteins extracted from the seed of mabinlang (Capparis masaikai Levl.), a plant growing in Yunnan province of China. There are four homologues.

Why does Mabinlin 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 Mabinlin?

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 Mabinlin.