Differential conformational dynamics in the closely homologous FK506-binding domains of FKBP51 and FKBP52.
Differential conformational dynamics in the closely homologous FK506-binding domains of FKBP51 and FKBP52.
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DOI：
10.1042/bj20140232
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发表时间：
2014-07-01
期刊：
影响因子：
--
通讯作者：
Hernández G
中科院分区：
文献类型：
--
作者：
Mustafi SM;LeMaster DM;Hernández G
FKBP51(FK506结合蛋白，51 kDa)和FKBP52(FK506结合蛋白，52 kDa)作为HSP90(热休克蛋白90)的辅助伴侣，在调节类固醇受体复合体的激素亲和力和核转运方面起拮抗作用。FKBP51中的Leu119与FKBP52中的Pro119的交换在很大程度上逆转了FKBP51和FKBP52的类固醇受体活性。为了检验构象动力学/可塑性的差异是否与已报道的受体活性的变化有关，对FKBP51和FKBP52的N端FKBP结构域及其残基交换变体进行了15N-核磁共振弛豫测量。这两种蛋白质在皮秒-纳秒的时间框架内表现出类似的运动模式，并且在中央薄片的β3a链中表现出少量的15N线宽，这表明在微秒-毫秒的时间框架内的运动。只有FKBP51结构域在邻近的β3凸起(FKBP12的40‘S环)和整个长的β4-β5环(FKBP12的80’S环)中显示出更大的线宽。β4-β5环末端的L119P突变完全抑制了该环的线宽，同时部分抑制了邻近β2和β3a链的线宽。互补的FKBP52的P119L和P119L/P124S变异体在β4-β5环上产生了与FKBP51相似的线条加宽模式，尽管分别只有FKBP51的20%和60%。然而，尽管FKBP51和FKBP52的β4-β5环与β3a链之间的堆积作用在结构上非常相似，但β3a链的线条加宽不受FKBP52的P119L或P119L/P124S突变的影响。与FKBP52不同，FKBP51的FK1结构域在β3凸起和β4-β5环中表现出微秒级的构象动力学，这是已知的蛋白质信号相互作用的部位。交换残基119的结果改变了构象动力学，这让人想起已报道的类固醇受体活性的调节。
As co-chaperones of Hsp90 (heat-shock protein 90), FKBP51 (FK506-binding protein of 51 kDa) and FKBP52 (FK506-binding protein of 52 kDa) act as antagonists in regulating the hormone affinity and nuclear transport of steroid receptor complexes. Exchange of Leu119 in FKBP51 for Pro119 in FKBP52 has been shown to largely reverse the steroid receptor activities of FKBP51 and FKBP52. To examine whether differences in conformational dynamics/plasticity might correlate with changes in the reported receptor activities, 15N-NMR relaxation measurements were carried out on the N-terminal FKBP domains of FKBP51 and FKBP52 as well as their residue-swapped variants. Both proteins exhibit a similar pattern of motion in the picosecond–nanosecond timeframe as well as a small degree of 15N line-broadening, indicative of motion in the microsecond–millisecond timeframe, in the β3a strand of the central sheet. Only the FKBP51 domain exhibits much larger line-broadening in the adjacent β3 bulge (40′s loop of FKBP12) and throughout the long β4–β5 loop (80′s loop of FKBP12). The L119P mutation at the tip of the β4–β5 loop completely suppressed the line-broadening in this loop while partially suppressing the line-broadening in the neighbouring β2 and β3a strands. The complementary P119L and P119L/P124S variants of FKBP52 yielded similar patterns of line-broadening for the β4–β5 loop as that for FKBP51, although only 20% and 60% as intense respectively. However, despite the close structural similarity in the packing interactions between the β4–β5 loop and the β3a strand for FKBP51 and FKBP52, the line-broadening in the β3a strand is unaffected by the P119L or P119L/P124S mutations in FKBP52. Unlike FKBP52, the FK1 domain of FKBP51 exhibits microsecond–millisecond conformational dynamics in the β3 bulge and the β4–β5 loop, known sites of protein signalling interactions. Swapping residue 119 yields altered conformational dynamics in a pattern reminiscent of reported modulations in steroid receptor activity.