Helicobacter pylori Strain 51의 보유한 Type II 제한효소 (Hpy51-I)의 특성

• Published in: Journal of bacteriology and virology Vol. 31; no. 3; pp. 207 - 215
• Main Authors: 조명제, 박정욱, 전병삼, 박정원, 변은영, 이선경, 박예형, 송재영, 이우곤, 백승철, 최여정, 정선애, 최미영, Cho, Myung-Je, Park, Jeong-Uck, Jeon, Beong-Sam, Pack, Jeong-Won, Byun, Eun-Young, Lee, Sun-Kyung, Park, Ye-Hyoung, Song, Jae-Young, Lee, Woo-Kon, Baik, Seung-Chul, Choi, Yeo-Jeong, Jung, Seun-Ae, Choe, Mi-Young
• Format: Journal Article
• Language: Korean
• Published: 2001
• Subjects: H; pylori; Type II restriction endonuclease
• ISSN: 1598-2467; 2093-0429

This study describes the purification and characterization of type II restriction endonuclease of Helicobacter pylori in order to understand the DNA restriction and modification of H pylori. H pylori cell extract was subjected to polyethyleneimine treatment, salt precipitation, heparine-sepharose column chromatography, and fast protein liquid chromatogrphy (FPLC) using Resource Q column and Mono Q column to purify the type II restriction endonuclease. Hpy51-I was characterized to recognize the sequneces 5'-GT(G/C)AC-3', yielding 5-base 5' protruding ends. The restriction sequence was identical to that of Tsp 45 I. The enzyme exhibited its maximal activity in the presence of $10{\sim}20\;mM$ NaCl, but was inhibited completely in the presence of more than 80 mM NaCl. The enzyme showed its maximal activity in the presence of $1{\sim}10\;mM\;MgCl_2$. The optimal pH and temperature for enzyme activity was pH 9.0 and $37^{\circ}C$, respectively. $MnCl_2$ could not substitute for $MgCl_2$ in reaction mixture. And addition of ${\beta}$-mercaptoethanol and bovine serum albumin in reaction mixture led to loss of enzyme activity of Hpy51-I. The whole cell extract of H. pylori strain 51 was confirmed to carry the enzyme activity for methylation of Hpy51-I-recognised sequence. Hpy51-I digested genomic DNAs of enteric bacteria to less than I kb while it could not cut the genomic DNAs of H. pylori isolates. In this study, the type II restriction enzyme (Hpy51-I) of H. pylori was identified and characterized its biochemical properties, demonstrating that Hpy51-I might be one of the barriers for preventing the introduction of foreign DNAs into H. pylori.