Friday, April 20, 2012


Article Summaries:
Structure and Function of Type 2 restriction endonucleases
               Currently, there are more than 3000 type 2 restriction endonucleases discovered.  Restriction enzymes cleave specific regions of DNA. Specifically, type 2 restriction endonucleases do not require ATP Hydrolysis and there are also subdivisions that are more specific categories. Bgl2 is part of the EcoRI family as a sub category for type 2 restriction endonucleases. The sequence cleaved by Bgl2 is  AGATCT, and when it cleaves, there are sticky ends.  The binding site of Bgl2 encircles the DNA and approaches from the major groove side of the DNA and it also comes in contact with the minor groove side.  This article also goes into the specific residues that interact with each part of the DNA. Collectively in the entire interaction with DNA, there are 5 carbon bonds with the minor groove and 14 hydrogen bonds to the major groove.  “Altogether there are 28 backbone contacts, 20 of them are water-mediated”
Pingoud, Alfred, and Albert Jeltsch. "Structure and Function of Type 2 Restricstion Endonucleases." Nucleic Acids Reasearch 29.18 (2001): 3705-27. Print.
Institut für Biochemie (FB 08), Justus-Leibig-Univerität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany

Purification and Properties of the Restriction Endonuclease BglII from Baccillus globigii
               BglI and BglII were first discovered in Baccillus globigii and found to be useful  in recombinant DNA experiments. Both BglI and BglII recognize the same section of DNA.  This paper discusses the purification of BglII and properties discovered for BglII. For enzymatic activity for BglII, Magnesium must be present. Sodium Chloride is also required for some stimulation of enzymatic activity. The researchers found that the optimum pH is higher than most other restrictions enzymes, but they also say that this optimum might be different when other labs research it.  They tested other ions to see if they would activate enzymatic activity and the ones that did were Mn2+, Zn2+, Cd2+, and Ni2+; and Mn2+ was observed to be better than low concentrations of Mg2+.  They also looked at the interactions with DNA. They found that BglII does not significantly unwind DNA and that it cleaves both strands almost simultaneously.
Imber, Roland, and Thomas A. Bickle. "Purification and Properties of the Restriction Endonuclease BglII from Baccillus globigii." Federation of the Societies of Biochemistry and Molecular Biology 117 (1981): 395-99. Print.
Microbiology Department, Biozentrum, University of Basel

Structure of Free BglII reveals an unpredicted scissor-like motion for opening and endonuclease
               This article analyses the movement of BglII in a scissor like motion. BgkII has 223 amino acids in its structure and it is a dimer, made up of two units. Each unit has two loops that enclose the DNA by reaching around the minor groove. The active site residues are only exposed for catalysis when a group called the lever is in the up position, interacting with the DNA.
Lukacs, Christine M., Rebecca Kucera, Ira Schildkraut, and Aneel k. Aggarwal. "Structure of Free BglII reveals an unpredicted scissor-like motion for opening and endonuclease." Nature Publishing Group 8.2 (2001). Print.
Structural Biology Program, Department of Physiology and Biophysics, Mount  Sinai School of Medicine

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