英和和英

出典:『Wikipedia』 (2011/03/04 23:32 UTC 版)

英語による解説

引用

BglII (pronounced "bagel two") is a type II restriction endonuclease enzyme isolated from certain strains of Bacillus globigii. The principal function of restriction enzymes is the protection of the host genome against foreign DNA but they may also have some involvement in recombination and transposition. Like most type II restriction enzymes BglII consists of two identical subunits that form a homodimer around the DNA double helix. Each monomer is 223 amino acids and symmetrically bind both sides of the unique palindromic nucleotide sequence AGATCT, cleaving the scissile phosphodiester bond between the first Adenine and Guanine nucleotides on both strands of the DNA molecule creating sticky ends with 5' end overhangs. Being a type II restriction enzyme BglII does not require ATP (adenosine triphosphate) for its enzymatic function but only requires association with a divalent metal cation, most likely Mg²⁺. Unlike other restriction enzymes of its class, BglII has been show to possess some unique structural characteristics such as a β-sandwich subdomain and appears to undergo a unique conformational change upon dimerization, but it’s overall structure and mechanism of catalysis remain consistent with other type II restriction enzymes. Restriction Endonuclease enzymes play a very important role in modern molecular cloning techniques. Because of their unique recognition/cut sites restriction enzymes can be used to precisely and controlably cut DNA in specific locations. Once cut, scientist can then insert a desired DNA fragment that contains complementary "sticky ends" into the linearized DNA and ligate them together to create an engineered cloning vector.