Flexibility and ligand exchange in a buried cavity mutant of T4 lysozyme studied by multinuclear NMR
Flexibility and ligand exchange in a buried cavity mutant of T4 lysozyme studied by multinuclear NMR
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DOI：
10.1021/bi001351t
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发表时间：
2000-10-17
期刊：
影响因子：
2.9
通讯作者：
Kay, LE
中科院分区：
文献类型：
--
作者：
Mulder, FAA;Hon, B;Kay, LE
T4 溶菌酶的 Leu99-->Ala 突变体在其 C 端结构域的核心包含一个大的内腔，能够可逆地结合小的疏水化合物。尽管空腔被完全掩埋，但苯或氙等分子可以快速进出。通过测量主链酰胺和侧链甲基核的 NMR 自旋弛豫率，将未配体蛋白质的动力学与野生型蛋白质进行了比较。发现空腔周围的许多残留物受到速率为 1500 +/- 200 s(-1) 的化学交换过程的影响，该过程在添加饱和量的配体氙后被淬灭。讨论了 T4 溶菌酶突变体的结构、动力学和能量学之间的关系。
The Leu99-->Ala mutant of T4 lysozyme contains a large internal cavity in the core of its C-terminal domain that is capable of reversibly binding small hydrophobic compounds. Although the cavity is completely buried, molecules such as benzene or xenon can exchange rapidly in and out. The dynamics of the unliganded protein have been compared to the wild-type protein by measuring the NMR spin relaxation rates of backbone amide and side chain methyl nuclei. Many residues surrounding the cavity were found to be affected by a chemical exchange process with a rate of 1500 +/- 200 s(-1), which is quenched upon addition of saturating amounts of the ligand xenon. The relationship between the structure, dynamics, and energetics of the T4 lysozyme mutant is discussed.