MMEI, A CLASS-IIS RESTRICTION-ENDONUCLEASE - PURIFICATION AND CHARACTERIZATION

被引：22

作者：

TUCHOLSKI, J ^{[1
]}

SKOWRON, PM ^{[1
]}

PODHAJSKA, AJ ^{[1
]}

机构：

[1] UNIV GDANSK,DEPT MICROBIOL,PL-80822 GDANSK,POLAND

来源：

GENE | 1995年 / 157卷 / 1-2期

关键词：

CLASS-IIS RESTRICTION ENDONUCLEASE; METHYLOPHILUS METHYLOTROPHUS; MMEII ENDONUCLEASE; PROTEIN PURIFICATION; RESTRICTION-MODIFICATION;

D O I：

10.1016/0378-1119(94)00787-S

中图分类号：

Q3 [遗传学];

学科分类号：

071007 ; 090102 ;

摘要：

Two restriction endonucleases, MmeI and MmeII, from Methylophilus methylotrophus were purified to homogeneity. Both enzymes belong to the class-II restriction endonucleases (ENases) but exhibit very different enzymatic and physical properties. MmeII is a typical member of class-II ENases. It is a polymeric protein composed of 50-kDa subunits. In contrast to MmeII, MmeI is a monomeric protein of 101 kDa, cleaving a DNA molecule 20/18 nucleotides away from the asymmetric recognition sequence (5'-TCCRAC-3'); therefore, it is classified as a member of subclass-IIS. MmeI has an pi of 7.85 and is active in the pH range 6.5 to 10 with the optimum at 7 to 8. Increasing salt concentration creates an inhibitory effect on MmeI: 40 mM KCl decreases activity by 50%, 100 mM completely inhibits DNA cleavage. Tris HCl (pH 7.5) at a concentration exceeding 20 mM inhibits MmeI activity. Mg2+ stimulates MmeI in the range of 0.2 to 35 mM, with the optimum between 0.5 and 10 mM.

引用

页码：87 / 92

页数：6

共 18 条

[1] ISOLATION AND COMPUTER-AIDED CHARACTERIZATION OF MMEI, A TYPE-II RESTRICTION ENDONUCLEASE FROM METHYLOPHILUS-METHYLOTROPHUS [J].