Mabinlin

protein
Name = Mabinlin 1
caption = Also known as: Mabinlin I, MAB I


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HGNCid =
Symbol = 2SS1_CAPMA
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UniProt = P80351
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LocusSupplementaryData = protein
Name = Mabinlin 2
caption = Also known as: Mabinlin II, MAB II

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HGNCid =
Symbol = 2SS2_CAPMA
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EntrezGene =
OMIM =
RefSeq =
UniProt = P30233
PDB = 2DS2
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Band =
LocusSupplementaryData = protein
Name = Mabinlin 3
caption = Also known as: Mabinlin III, MAB III


width =
HGNCid =
Symbol = 2SS3_CAPMA
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OMIM =
RefSeq =
UniProt = P80352
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LocusSupplementaryData = protein
Name = Mabinlin 4
caption = Also known as: Mabinlin IV, MAB IV


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HGNCid =
Symbol = 2SS4_CAPMA
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EntrezGene =
OMIM =
RefSeq =
UniProt = P80353
PDB =
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Arm =
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LocusSupplementaryData =

Mabinlins are sweet-tasting proteins extracted from the seed of Mabinlang ("Capparis masaikai Levl."), a Chinese plant growing in Yunnan province. There are four homologues. Mabinlin-2 was first isolated in 1983Z Hu and M He. Studies on mabinlin, a sweet protein from the seeds of Capparis masaikai levl. I. extraction, purification and certain characteristics. Acta Botan. Yunnan. 1983, 5, 207–212.] and characterised in 1993, [http://www.nutritionj.com/pubmed/8425538/ X Liu, S Maeda, Z Hu, T Aiuchi, K Nakaya, Y Kurihara. Purification, complete amino acid sequence and structural characterization of the heat-stable sweet protein, mabinlin II. Eur J Biochem 1993. 211(1–2):281-7.] ] and is the most extensively studied of the four. The other variants of mabinlin-1, -3 and -4 were discovered and characterised in 1994. [http://www.nutritionj.com/pubmed/8055976/ S Nirasawa, T Nishino, M Katahira, S Uesugi, Z Hu, Y Kurihara. Structures of heat-stable and unstable homologues of the sweet protein mabinlin. Eur J Biochem 1994, 223(3):989-95.] ]

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. [http://www.expasy.org/uniprot/P80351 UniProtKB/Swiss-Prot database entry for 2SS1_CAPMA (P80351).] ] [http://www.expasy.org/uniprot/P30233 UniProtKB/Swiss-Prot database entry for 2SS2_CAPMA (P30233).] ] [http://www.expasy.org/uniprot/P80352 UniProtKB/Swiss-Prot database entry for 2SS3_CAPMA (P80352).] ] [http://www.expasy.org/uniprot/P80353 UniProtKB/Swiss-Prot database entry for 2SS4_CAPMA (P80353).] ]

The molecular weights of Mabinlin-1, Mabinlin-3 and Mabinlin-4 are 12.3 kDa, 12.3 kDa and 11.9 kDa, respectively. [http://www.nutritionj.com/pubmed/8055976/ S Nirasawa, T Nishino, M Katahira, S Uesugi, Z Hu, Y Kurihara. Structures of heat-stable and unstable homologues of the sweet protein mabinlin. Eur J Biochem 1994, 223(3):989-95.] ]

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. 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. [http://www.nutritionj.com/pubmed/8425538/ X Liu, S Maeda, Z Hu, T Aiuchi, K Nakaya, Y Kurihara. Purification, complete amino acid sequence and structural characterization of the heat-stable sweet protein, mabinlin II. Eur J Biochem 1993. 211(1–2):281-7.] ] [http://www.nutritionj.com/pubmed/9715665 Kohmura M, Ariyoshi Y: Chemical synthesis and characterization of the sweet protein mabinlin II. Biopolymers 1998, 46(4):215-23. ] ]

Mabinlin-2 is the sweet-tasting protein with the highest known thermostability, [http://www.nutritionj.com/pubmed/10930844/ RJ Guan, JM Zheng, Z Hu, DC Wang. Crystallization and preliminary X-ray analysis of the thermostable sweet protein mabinlin II. Acta Crystallogr D Biol Crystallogr 2000, 56(Pt 7):918-9.] ] which is due to the presence of the four disulfide bridges. [http://www.nutritionj.com/pubmed/8399391/ S Nirasawa, X Liu, T Nishino, Y Kurihara. Disulfide bridge structure of the heat-stable sweet protein mabinlin II. Biochim Biophys Acta 1993, 1202(2):277-80.] ] 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. [http://www.nutritionj.com/pubmed/8055976/ S Nirasawa, T Nishino, M Katahira, S Uesugi, Z Hu, Y Kurihara. Structures of heat-stable and unstable homologues of the sweet protein mabinlin. Eur J Biochem 1994, 223(3):989-95.] ]

Sweetness properties

Mabinlins sweetness were estimated to be about 100-400 times that of sucrose on weight basis, [http://www.nutritionj.com/pubmed/8425538/ X Liu, S Maeda, Z Hu, T Aiuchi, K Nakaya, Y Kurihara. Purification, complete amino acid sequence and structural characterization of the heat-stable sweet protein, mabinlin II. Eur J Biochem 1993. 211(1–2):281-7.] ] [http://www.nutritionj.com/pubmed/8055976/ S Nirasawa, T Nishino, M Katahira, S Uesugi, Z Hu, Y Kurihara. Structures of heat-stable and unstable homologues of the sweet protein mabinlin. Eur J Biochem 1994, 223(3):989-95.] ] which make them less sweet than thaumatin (3000 times) but elicit a similar sweetness profile. [http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&uid=1418601&cmd=showdetailview Y Kurihara. 1992. Characteristics of antisweet substances, sweet proteins, and sweetness-inducing proteins. Crit. Rev. Food Sci. Nutr. 32:231-252.] ]

The sweetness of mabinlin-2 is unchanged after 48 hours incubation at boiling point. [http://www.nutritionj.com/pubmed/8425538/ X Liu, S Maeda, Z Hu, T Aiuchi, K Nakaya, Y Kurihara. Purification, complete amino acid sequence and structural characterization of the heat-stable sweet protein, mabinlin II. Eur J Biochem 1993. 211(1–2):281-7.] ]

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. [http://www.nutritionj.com/pubmed/8055976/ S Nirasawa, T Nishino, M Katahira, S Uesugi, Z Hu, Y Kurihara. Structures of heat-stable and unstable homologues of the sweet protein mabinlin. Eur J Biochem 1994, 223(3):989-95.] ] [http://www.ffcr.or.jp/zaidan/FFCRHOME.nsf/7bd44c20b0dc562649256502001b65e9/ea044c8f392c31d5492568a20029dd20/$FILE/174-10.pdf Y Kurihara and S Nirasawa. Structures and activities of sweetness-inducing substances (miraculin, curculin, strogin) and the heat-stable sweet protein, mabinlin. Foods and Food Ingredients Journal of Japan 1997.174:67-74.] ]

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. [http://www.nutritionj.com/pubmed/9715665/ Kohmura M, Ariyoshi Y: Chemical synthesis and characterization of the sweet protein mabinlin II. Biopolymers 1998, 46(4):215-23. ] ]

Mabinlin-2 has been expressed in transgenic potato tubers, but no explicit results have been reported yet.LW Xiong and S Sun. Molecular cloning and transgenic expression of the sweet protein mabinlin in potato tubers. Plant Physiology 1996, 111, 147.] However, patents to protect production of recombinant mabinlin by cloning and DNA sequencing have been issued.US patent|6051758| S Sun, L Xiong, Z Hu and H Chen. Recombinant Sweet protein Mabinlin. US PAT No. 6,051,758]

References

ee also

* Brazzein
* Pentadin
* Monellin
* Thaumatin