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Mung bean nuclease (Nuclease MB) is a nuclease derived from sprouts of the mung bean (Vigna radiata) that removes nucleotides in a step-wise manner from single-stranded DNA molecules (ssDNA) and is used in biotechnological applications to remove such ssDNA from a mixture also containing double-stranded DNA (dsDNA). This enzyme is useful for transcript mapping, removal of single-stranded regions in DNA hybrids or single-stranded overhangs produced by restriction enzymes, etc. It has an activity similar to Nuclease S1 (both are EC 3.1.30.1), but it has higher specificity for single-stranded molecules.^[1]

The enzyme degrades single-stranded DNA or RNA to nucleoside 5’-monophosphates, but does not digest double-stranded DNA, double-stranded RNA, or DNA / RNA hybrids. Mung Bean Nuclease catalyzes the specific degradation of single-stranded DNA or RNA, and produces mono and oligonucleotides carrying a 5′-P terminus. Mung bean nuclease has a stringent single-stranded specificity for DNA or RNA.

Mung bean nuclease has an estimated molecular weight of 39 kDa by SDS-PAGE. A glycoprotein, 29% of this mass is sugars.^[2] As of April 2019^[update], the specific gene encoding for this protein is unknown, and all production relies on a purification process on bean sprouts from 1980.^[1] Some is known about its structure, with one exposed Cysteine residue and 3 pairs of disulfide bonds. Some is known about its amino acid composition.^[2]

Requirements

Mung bean nuclease requires Zn²⁺. The addition of EDTA or SDS causes irreversible inactivation. Mung bean nuclease is not active at pH below 4.6, nor at low salt concentration.

Description

Nuclease MB is a specific DNA and RNA exo-endonuclease which will degrade single-stranded extensions from the ends of DNA and RNA molecules, leaving blunt, ligatable ends. Its higher single-strand specificity makes it the enzyme of choice for most applications requiring a single-strand-specific nuclease.

Unlike S1 Nuclease, Mung Bean Nuclease will not cleave the intact strand of nicked duplex DNA.

Its ability to recognise double-stranded nucleic acids depends on the base sequence.

It tends to cleave at ApN and at T(U) pN. It completely degrades ApA, but does not degrade G and C. Unlike S1 Nuclease, it does not cleave the strand opposite to that which has been nicked.

Mung Bean Nuclease catalyzes the specific degradation of single-stranded DNA or RNA, and produces mono- and oligonucleotides carrying a 5′-P terminus.

More than 1000- fold amount of enzyme can degrade oligomer into all mononucleotides.

An excess of the enzyme is required to degrade double-stranded DNA or RNA and DNA-RNA hybrids, and in this case, AT-rich regions are selectively degraded.

This enzyme work well at A↓pN, T ↓pN sites, and especially A↓pN sites are 100% degraded.

However, it is difficult to degrade C↓pC, C↓pG site.

Mung bean exonuclease is a nuclease derived from mung beans that removes nucleotides in a step-wise manner from single stranded DNA molecules and is used to remove such ssDNA from a mixture also containing double stranded DNA (dsDNA).

Unit Definition:

One unit of Mung Bean Nuclease converts 1 µg of heat-denatured calf thymus DNA into an acid-soluble form in 1 minute at 37 °C under standard assay conditions.

Applications in biotechnology and biochemical research

Removal of hairpin loops during cDNA synthesis.
High-resolution mapping of the termini and exon structures of RNA transcripts (commonly termed Berk-Sharp or S1 Mapping) using either internal-labelled or end-labelled probes.
Restriction-site modification or removal by digestion of single-stranded protruding ends.
Cleavage of single-basepair mismatches, as a replacement for CEL 1 Nuclease in TILLING.
Unidirectional deletion of large DNA (in combination with Exonuclease III) to generate ordered deletions for sequencing.
Removal of 3´ and 5´ extensions from DNA or RNA termini.
Transcriptional mapping.
Cleavage of hairpin loops.
Excision of gene coding sequences from genomic DNA.

References

^ ^a ^b "BRENDA: 3.1.30.1".
^ ^a ^b Eun, HM (1996). "Nucleases". Enzymology primer for recombinant DNA technology. Academic Press. pp. 145–232. doi:10.1016/B978-012243740-3/50006-5. ISBN 978-0-12-243740-3.

@@ Line 1: / Line 1: @@
+{{Short description|Enzyme used to distinguish between single and double stranded DNA and RNA}}
+{{Multiple issues|
-'''Mung bean exonuclease''' is a [[nuclease]] derived from [[mung bean]]s that removes nucleotides in a step-wise manner from single stranded [[DNA]] molecules and is used to remove such ssDNA from a mixture also containing double stranded DNA (dsDNA). 	Mungbean Nuclease is a singlestrand- specific nuclease purified from sprouts of mung bean Vigna radiata.
+{{Refimprove|date=September 2019}}
+{{MOS|date=September 2017}}
+}}
+'''Mung bean nuclease''' ('''Nuclease MB''') is a [[nuclease]] derived from sprouts of the [[mung bean]] (''Vigna radiata'') that removes nucleotides in a step-wise manner from [[single-stranded DNA]] molecules (ssDNA) and is used in biotechnological applications to remove such ssDNA from a mixture also containing [[double-stranded DNA]] (dsDNA). This enzyme is useful for transcript mapping, removal of single-stranded regions in DNA hybrids or single-stranded overhangs produced by [[restriction enzyme]]s, etc. It has an activity similar to [[Nuclease S1]] (both are EC 3.1.30.1), but it has higher specificity for single-stranded molecules.<ref name=brenda-EC>{{cite web |title=BRENDA: 3.1.30.1 |url=https://www.brenda-enzymes.org/enzyme.php?ecno=3.1.30.1}}</ref>
-	The enzyme degrades '''single-stranded DNA or RNA''' to nucleoside 5’-monophosphates, but '''does''' '''not digest double-stranded DNA, double-stranded RNA, or DNA / RNA hybrids.'''
-	Mung Bean Nuclease catalyzes the specific degradation of single-stranded DNA or RNA, and produces '''mono and oligonucleotides''' carrying a 5′-P terminus.
+The enzyme degrades single-stranded DNA or RNA to nucleoside 5’-monophosphates, but does not digest double-stranded DNA, double-stranded RNA, or DNA / RNA hybrids. Mung Bean Nuclease catalyzes the specific degradation of single-stranded DNA or RNA, and produces mono and oligonucleotides carrying a 5′-P terminus. Mung bean nuclease has a stringent single-stranded specificity for DNA or RNA.
-	Mung bean exonuclease is a nuclease derived from mung beans that removes nucleotides in a step-wise manner from single stranded DNA molecules and is used to remove such ssDNA from a mixture also containing double stranded DNA (dsDNA).
-'''Molecular Weight:'''
+Mung bean nuclease has an estimated molecular weight of 39 kDa by [[SDS-PAGE]]. A glycoprotein, 29% of this mass is sugars.<ref name=eun>{{cite book |last1=Eun |first1=HM |title=Enzymology primer for recombinant DNA technology |pages=145–232 |publisher=Academic Press |isbn=978-0-12-243740-3 |chapter=Nucleases |doi=10.1016/B978-012243740-3/50006-5|year=1996 }}</ref> {{As of|2019|04}}, the specific gene encoding for this protein is unknown, and all production relies on a purification process on bean sprouts from 1980.<ref name=brenda-EC/> Some is known about its structure, with one exposed Cysteine residue and 3 pairs of disulfide bonds. Some is known about its [[pseudo amino acid composition|amino acid composition]].<ref name=eun/>
-Theoretical: 39 kDa
-Mung bean nuclease has a stringent single-stranded specificity for DNA or RNA and produces 5’-phosphoryl oligo- and mononucleotides. This enzyme is ideal for transcript mapping, removal of single-stranded regions in DNA hybrids or single-stranded overhangs produced by the restriction enzymes etc.
-Mung bean nuclease '''requires Zn2+'''. The addition of EDTA or SDS causes irreversible inactivation. Do not use at pH below 4.6. Mung bean nuclease '''should not be used at low salt concentration.'''
+==Requirements==
-'''Description:
+Mung bean nuclease requires Zn<sup>2+</sup>. The addition of [[Ethylenediaminetetraacetic acid|EDTA]] or [[Sodium dodecyl sulfate|SDS]] causes irreversible inactivation. Mung bean nuclease is not active at pH below 4.6, nor at low salt concentration.
-'''
-A single-strand specific DNA and RNA endonuclease which will degrade single-stranded extensions from the ends of DNA and RNA molecules, leaving blunt, ligatable ends.
+== Description ==
-Mung Bean Nuclease is a single-strand-specific nuclease purified from sprouts of the mung bean '''''Vigna''''''''''radiata'''''.
-Because Mung Bean Nuclease has higher specificity for ssDNA and RNA than S1 Nuclease, it is the enzyme of choice for most applications requiring a '''single-strand-specific nuclease'''.
+Nuclease MB is a specific DNA and RNA [[exo-endonuclease]] which will degrade single-stranded extensions from the ends of DNA and RNA molecules, leaving blunt, ligatable ends. Its higher single-strand specificity makes it the enzyme of choice for most applications requiring a single-strand-specific nuclease.
-Unlike S1 Nuclease, Mung Bean Nuclease will '''not cleave the intact strand of nicked duplex DNA.'''
+Unlike [[S1 nuclease|S1 Nuclease]], Mung Bean Nuclease will not cleave the intact strand of nicked duplex DNA.
-Its ability to recognize double-stranded nucleic acids '''depends on the base sequence.'''
+Its ability to recognise double-stranded nucleic acids depends on the base sequence.
 It tends to cleave at ApN and at T(U) pN. It completely degrades ApA, but does not degrade G and C. Unlike S1 Nuclease, it does not cleave the strand opposite to that which has been nicked.
 Mung Bean Nuclease catalyzes the specific degradation of single-stranded DNA or RNA, and produces mono- and oligonucleotides carrying a 5′-P terminus.
 More than 1000- fold amount of enzyme can degrade oligomer into all mononucleotides.
- An excess of the enzyme is required to degrade double-stranded DNA or RNA and DNA-RNA hybrids, and in this case, AT-rich regions are selectively degraded.
+An excess of the enzyme is required to degrade double-stranded DNA or RNA and DNA-RNA hybrids, and in this case, AT-rich regions are selectively degraded.
 This enzyme work well at A↓pN, T ↓pN sites, and especially A↓pN sites are 100% degraded.
 However, it is difficult to degrade C↓pC, C↓pG site.
 Mung bean exonuclease is a nuclease derived from mung beans that removes nucleotides in a step-wise manner from single stranded DNA molecules and is used to remove such ssDNA from a mixture also containing double stranded DNA (dsDNA).
 '''Unit Definition:'''
-One unit of Mung Bean Nuclease converts 1 µg of heat-denatured calf thymus DNA into an acid-soluble form in 1 minute at 37°C under standard assay conditions.
+One unit of Mung Bean Nuclease converts 1&nbsp;µg of heat-denatured calf thymus DNA into an acid-soluble form in 1 minute at 37&nbsp;°C under standard assay conditions.
+== Applications in biotechnology and biochemical research ==
-'''Applications'''
-•	Removal of hairpin loops during cDNA synthesis.
+* Removal of hairpin loops during cDNA synthesis.
+* High-resolution mapping of the termini and exon structures of RNA transcripts (commonly termed Berk-Sharp or S1 Mapping) using either internal-labelled or end-labelled probes.
+* Restriction-site modification or removal by digestion of single-stranded protruding ends.
+* Cleavage of single-basepair mismatches, as a replacement for CEL 1 Nuclease in TILLING.
+* Unidirectional deletion of large DNA (in combination with Exonuclease III) to generate ordered deletions for sequencing.
+* Removal of 3´ and 5´ extensions from DNA or RNA termini.
+* Transcriptional mapping.
+* Cleavage of hairpin loops.
+* Excision of gene coding sequences from genomic DNA.
+== References ==
-•	High-resolution mapping of the termini and exon structures of RNA transcripts (commonly termed Berk-Sharp or S1 Mapping) using either internal-labeled or end-labeled probes.
+{{reflist}}
+== Further reading ==
-•	Restriction-site modification or removal by digestion of single-stranded protruding ends.
+* Kowalski et al's many-article series from the 1970s: {{cite journal |last1=Kowalski |first1=David |last2=Kroeker |first2=Warren D. |last3=Laskowski |first3=M. |title=Mung bean nuclease I. 6. Physical, chemical, and catalytic properties |journal=Biochemistry |date=1976 |volume=15 |issue=20 |pages=4457–4463 |doi=10.1021/bi00665a019|pmid=9973 }}
+{{Esterases}}
-•	Cleavage of single-basepair mismatches, as a replacement for CEL 1 Nuclease in TILLING.
+{{Enzymes}}
+{{Portal bar|Biology|border=no}}
+[[Category:EC 3.1.30]]
-•	Unidirectional deletion of large DNA (in combination with Exonuclease III) to generate ordered deletions for sequencing.
-•	Removal of 3´ and 5´ extensions from DNA or RNA termini.
-•	Transcriptional mapping.
-•	Cleavage of hairpin loops.
-•	Excision of gene coding sequences from genomic DNA.
-•	Generation of new restriction sites.

v t e Enzymes
Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Diffusion-limited enzyme Cofactor Enzyme catalysis
Regulation	Allosteric regulation Cooperativity Enzyme inhibitor Enzyme activator
Classification	EC number Enzyme superfamily Enzyme family List of enzymes
Kinetics	Enzyme kinetics Eadie–Hofstee diagram Hanes–Woolf plot Lineweaver–Burk plot Michaelis–Menten kinetics
Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list) EC7 Translocases (list)