Rat brain hexokinase: the hydrophobic N-terminus of the mitochondrially bound enzyme is inserted in the lipid bilayer.
Rat brain hexokinase: the hydrophobic N-terminus of the mitochondrially bound enzyme is inserted in the lipid bilayer.
复制标题
大鼠脑己糖激酶：线粒体结合酶的疏水性 N 末端插入脂质双层中。
DOI：
10.1016/0003-9861(88)90090-2
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发表时间：
1988
影响因子：
3.9
通讯作者：
Wilson,JE
中科院分区：
文献类型：
--
作者：
Xie,GC;Wilson,JE
线粒体结合的大鼠脑己糖激酶标记的光活化试剂，3-（三氟甲基）-3-（m-[125 I]碘苯基）diazirine。这种高度疏水的试剂被强烈地分配到膜核心的疏水环境中，因此选择性地标记穿透膜的该区域的蛋白质的片段。己糖激酶的标记被证明限于分子的N-末端区域。通过用胰凝乳蛋白酶处理酶，去除了约80%的放射性标记，胰凝乳蛋白酶优先切割酶N末端的疏水性9-残基序列，认为剩余的20%可能与两个额外的疏水残基相关，紧邻该片段，但不易被胰凝乳蛋白酶切割。标记的酶被证明是依赖于维护与膜的协会。这些结果与模型一致，其中己糖激酶的结合涉及将11个残基的疏水N-末端“尾”（可能存在于α-螺旋二级结构中）插入膜的疏水核心。
Mitochondrially bound rat brain hexokinase was labeled with the photoactivatable reagent, 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)diazirine. This highly hydrophobic reagent is strongly partitioned into the hydrophobic environment of the membrane core, and thus selectively labels segments of a protein that penetrate this region of the membrane. Labeling of hexokinase was shown to be restricted to the N-terminal region of the molecule. Approximately 80% of the radiolabel was removed by treatment of the enzyme with chymotrypsin, which preferentially cleaves a hydrophobic 9-residue sequence at the extreme N-terminus of the enzyme, and it is considered likely that the remaining 20% was associated with two additional hydrophobic residues, immediately adjacent to this segment but not susceptible to cleavage by chymotrypsin. Labeling of the enzyme was shown to be dependent on maintenance of the association with the membrane. These results are consistent with a model in which binding of hexokinase involves insertion of an 11-residue hydrophobic N-terminal “tail,” possibly existing in α-helical secondary structure, into the hydrophobic core of the membrane.