Mung bean nuclease

Metal ions, especially Zn(II), play an important role in many enzyme-catalyzed reactions involving nucleic acids, such as DNA cleavage by zinc nuclease. Therefore, the binding of Zn(II) to a 19-mer double-stranded oligodeoxyribonucleotide was investigated to understand the role of zinc in DNA cleavage catalyzed by mung bean nuclease [107]. 

Mung bean nuclease, T4DNA polymerase (Novagen, Madison, WI). 

If you are using the restriction enzyme BseR I or another enzyme that produces overhangs, do not alter the DNA concentration in this step, because activity of the mung bean nuclease that is added directly to this reaction is concentration dependent. 

Instead of SI nuclease, mung bean nuclease (cleaner results with the same enzyme activities but much more expensive) or exonuclease VII can be used. Exonuclease VII is interesting since it requires a free 3 - or 5 -end for digestion and introns will be resistant. However, exonuclease VII is useful in combination with SI nuclease, particularly for short introns. 

Metal ions also participate in the functioning of other nucleases, although the structural details of their participation are not nearly as established as those for staphylococcal nuclease. DNAse I also requires Ca for its catalytic activity.SI endonuclease, mung bean nuclease, and Physarum polycephalem nuclease require zinc ion either as cofactors or intrinsically for nuclease activity, and the restriction enzyme EcoRI may also require intrinsically bound zinc ion. In terms of how the zinc ion might function in these enzymes, one can look both to staphylococcal nuclease and to bacterial alkaline phosphatase for some... 

Two clones, carrying a 5.2 kb insert in inverse orientations were isolated and mapped by restriction enzyme analysis. The two clones were used to construct deletion clones with the exonuclease Ill/mung bean nuclease system. Deletion clones containing the psbG homologons region were sequenced. 

These enzymes degrade DNA from the ends and cannot themselves generally introduce breaks within a strand. For example, mung bean nuclease... 

Nucleases.—On treatment of mung bean nuclease I, a glycoproteinaceous enzyme, with j8-D-2-acetamido-2-deoxyglucanase the molecular mass decreased from 3.9 x 10 to 3.1 x 10. The peptides produced on reduction of this enzyme with a thiol were of molecular mass 1.87 x 10 and 1.25 x 10, indicating that carbohydrate had been attached to both. Nuclease Pi from a Penicillium species, also a glycoproteinaceous enzyme, was decreased in size from 4.0 x 10 to 3.0 x 10 by the action of the eiuyme. 

This section describes two representative single-strand-specific endonucleases nuclease SI from a fungus Aspergillus oryzae and mung bean nuclease from mung bean sprouts. The two enzymes are very similar in many respects both are thermostable, zinc-dependent glycoproteins of similar size and they share most of the substrate specificities. The most pronounced difference that exists between... 

Mung bean nuclease, abbreviated here as nuclease MB, is a single-strand-specific endonuclease similar to nuclease SI. Nuclease MB is a glycoprotein with a similar molecular size (39 IcDa) and the functional properties of the two enzymes are also similar. For example, they produce 5 -mononucleotide and 5 -oligonucleotide products. For most practical purposes, nuclease MB can be used interchangeably with nuclease SI. 

Mung bean nuclease is obtained from mung bean sprouts (5). Nearly homogeneous enzymes have been prepared by using various purification procedures (2,17). 

---