Dynamical mapping of E-coli thioredoxin via C-13 NMR relaxation analysis
Dynamical mapping of E-coli thioredoxin via C-13 NMR relaxation analysis
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DOI：
10.1021/ja960877r
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发表时间：
1996-10-02
影响因子：
15
通讯作者：
Kushlan, DM
中科院分区：
文献类型：
--
作者：
LeMaster, DM;Kushlan, DM
核磁共振弛豫分析被用来表征氧化E的内部动力学。coli硫氧还蛋白在皮秒-纳秒和微秒-毫秒频率范围内的413 H-C和H-N键载体。C-13弛豫数据是利用具有交替的C-13-C-12-C-13...标记模式最丰富的网站。当与部分氘化结合时，这种标记模式提供了表现出动态可解释的弛豫行为的孤立的H-1-C-13 IS自旋对。侧链被发现表现出更广泛的动态范围比先前已被表征为主链共振。结构上埋的芳香族和亮氨酸侧链的动力学解释相关的主链侧链扭转振荡。发现表现出毫秒动力学的结构区域与侧链-主链或分叉主链氢键的存在强烈相关。在毫秒范围内表现出迁移率的活性位点二硫化物周围的核与其化学位移在还原时改变的核的集合密切对应。瞬时构象被解释为由于二硫键处的应变而增强的反应性。
NMR relaxation analysis was used to characterize the internal dynamics of oxidized E. coli thioredoxin in both the picosecond-nanosecond and microsecond-millisecond frequency ranges for 413 H-C and H-N bond vectors. The C-13 relaxation data was obtained utilizing protein samples possessing an alternating C-13-C-12-C-13... labeling pattern for most enriched sites. When combined with partial deuteration, this labeling pattern provides for isolated H-1-C-13 IS spin pairs exhibiting dynamically interpretable relaxation behavior. Side chains were found to exhibit a far broader range of dynamics than have been previously characterized for main chain resonances. The dynamics of structurally buried aromatic and leucine side chains are interpreted in terms of correlated main chain-side chain torsional oscillations. Structural regions exhibiting millisecond dynamics were found to correlate strongly with the presence of side chain-main chain or bifurcated main chain hydrogen bonds. Nuclei around the active site disulfide that exhibit mobility in the millisecond range correspond closely to the set of nuclei whose chemical shifts are altered upon reduction. The transient conformation is interpreted in terms of enhanced reactivity due to strain at the disulfide linkage.