Saturday, April 21, 2012

Bgl II

          Bgl II is a restriction endonuclease, meaning that it cleaves a specific section of DNA. Bgl II is made up of two units; together the units encircle the DNA.
DNA is depicted in blue and Bgl II is orange
DNA is Blue and each unit it a different shade of orange
Bgl II, as well as Bgl I, were first discovered in Baccillus globigii, and were found useful in recombinant DNA experiment. Bgl II has 223 amino acids and each unit has two loops that enclose the DNA.

From this angle, the loops depicted in dark orange are visibly interacting
  Collectively in the entire interaction with DNA, there are 5 carbon bonds with the minor groove and 14 hydrogen bonds to the major groove.

          Bgl II scans the DNA from the major groove side and approaches the DNA from the major groove side. The enzyme uses a scissor like motion to bind with the DNA unlike other type two endonuclease restriction enzymes in its classification. When it is in the relaxed free position, the enzyme looks like this:

When Bgl II is bound to DNA it is in this position:

In addition to the scissor like motion, the loops that enclose the DNA are bent back in the free position, then bend over the DNA when Bgl II is interacting with the DNA.

          Ions present in solution with Bgl II are important to the activity. The ion Mg 2+ activates Bgl II the most, and the presence of NaCl aids in the activity.
          Bgl II binds and cleaves the same section of DNA as Bgl I. Type two restriction endonucleases cleave DNA without the use of ATP. Bgl II specifically cleaves a section leaving sticky ends. The place where the DNA is broken is marked with orange arrows in the picture below:
Bgl II does not significantly unwind the DNA when they are interacting and cleaves both Strands of DNA simultaneously, which is not common for restriction endonucleases.

          Bgl II is used in various experiments. One use is to break down large segments of DNA to be analyzed with Gel Electrophoresis. Also with this use, it is possible to determine if the site exists that Bgl II cleaves by seeing if the DNA traveled on the Gel; if there are multiple places where Bgl II cleaves, then there would be multiple small fragments. Endonuclease restriction enzymes are commonly used in Biotechnology experiments. Specifically, Bgl II is used in the insertion of gene segments into a section of DNA, such as a plasmid, or the deletion of a segment. This use of Bgl II is important in the replication of genes and the study of the results of changing DNA sequences.

The funny thing when talking about this protein is what do you call it: Bgl II
Photos taken from various blog posts then edited for resulting pictures

(All images were created for this page. The last image was two pictures taken from various blogs, then edited for this blog)

  • 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
  • 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
  • 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

1 comment:

  1. Good post, Steph. Sorry it took me so long to comment. Overall, I think it looks pretty good. The chemistry is well-explained and you made good use of visuals.

    However, I'm curious about the more practical aspects of the protein. Are there any known diseases associated with it? What sort of research is currently being done?

    Also, right above your picture with the DNA sequence, there's a minor typo: it says "bellow" when it should say "below." Just wanted to make sure you had a chance to catch that. :)