Escherichia coli lac repressor is elongated with its operator DNA binding domains located at both ends.
Escherichia coli lac repressor is elongated with its operator DNA binding domains located at both ends.
复制标题
大肠杆菌 lac 阻遏蛋白被拉长，其操纵子 DNA 结合域位于两端。
DOI：
10.1016/0022-2836(82)90465-x
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发表时间：
1982
影响因子：
5.6
通讯作者：
Steitz,TA
中科院分区：
文献类型：
--
作者：
McKay,DB;Pickover,CA;Steitz,TA
From small-angle X-ray scattering experiments on solutions ofEscherichia coli lacrepressor and repressor tryptic core, we conclude that the domains of repressor that bind to operator DNA lie at the ends of an elongated molecule. The addition of the inducer, isopropyl-β-d-thiogalactoside, to either repressor or core does not produce a measurable structural change, since the radius of gyration of repressor is 40.3 ± 1.9 Å without and 42.2 ± 1.7 Å with isopropyl-β-d-thiogalactoside; the core radius of gyration is 35.4 ± 1.1 Å without ligand and 36.3 ± 1.1 Å with isopropyl-β-d-thiogalactoside. In the context of data from single crystals of repressor and core, the measured radii of gyration are shown to be consistent with a core (or repressor) molecule of dimensional anisotropy 1: (1.5 to 2.0): (3.0 to 4.0). The 5 Å difference in radius of gyration between native and core repressor is interpreted to mean that the amino terminal 59 residues (headpieces) lie at the ends of an elongated repressor molecule. This structure implies that the repressor may have DNA binding sites, consisting of two adjacent headpieces, on each end of the molecule and this binds to the DNA with its long axis perpendicular to the DNA.
