Biliverdin Reductase B Dynamics Are Coupled to Coenzyme Binding.
Biliverdin Reductase B Dynamics Are Coupled to Coenzyme Binding.
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DOI：
10.1016/j.jmb.2018.06.015
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发表时间：
2018-09-14
影响因子：
5.6
通讯作者：
Eisenmesser EZ
中科院分区：
文献类型：
--
作者：
Paukovich N;Xue M;Elder JR;Redzic JS;Blue A;Pike H;Miller BG;Pitts TM;Pollock DD;Hansen K;D'Alessandro A;Eisenmesser EZ
胆绿素还原酶B（BLVRB）是一种新发现的细胞氧化还原调节剂，催化多种底物的NADPH依赖性还原。通过质谱分析，我们鉴定了成熟红细胞中高水平的BLVRB，突出了BLVRB在氧化还原调节中的重要性。然而，在conezyme/底物结合过程中发生的BLVRB构象变化以及BLVRB功能中的动力学作用仍然未知。通过NMR、动力学和等温滴定量热法研究的组合，我们确定BLVRB与其辅酶的结合比其底物紧密500倍。虽然载脂蛋白BLVRB的活性位点在多个时间尺度上是高度动态的，但活性位点动态在很大程度上在holo BLVRB内被淬灭，其中动态被重新分配到酶的其他区域。我们发现，Arg 78-Ala的单点突变导致活性位点微毫秒运动的增加和辅酶结合的微观速率常数的增加。这表明改变BLVRB活性位点动力学可以直接引起功能特征的变化。因此，我们的研究解决了apo和holo BLVRB的溶液行为，并确定了酶动力学在辅酶结合中的作用。
Biliverdin reductase B (BLVRB) is a newly identified cellular redox regulator that catalyzes the NADPH-dependent reduction of multiple substrates. Through mass spectrometry analysis, we identified high levels of BLVRB in mature red blood cells, highlighting the importance of BLVRB in redox regulation. The BLVRB conformational changes that occur during conezyme/substrate binding and the role of dynamics in BLVRB function, however, remain unknown. Through a combination of NMR, kinetics, and isothermal titration calorimetry studies, we determined that BLVRB binds its coenzyme 500-fold more tightly than its substrate. While the active site of apo BLVRB is highly dynamic on multiple timescales, active site dynamics are largely quenched within holo BLVRB, in which dynamics are redistributed to other regions of the enzyme. We show that a single point mutation of Arg78➔Ala leads to both an increase in active site micro-millisecond motions and an increase in the microscopic rate constants of coenzyme binding. This demonstrates that altering BLVRB active site dynamics can directly cause a change in functional characteristics. Our studies thus address the solution behavior of apo and holo BLVRB and identify a role of enzyme dynamics in coenzyme binding.
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DOI：
10.1073/pnas.1314303110
发表时间：
2013-10-08
影响因子：
11.1
作者：
Li, Ying;Altorelli, Nicole L.;Palmer, Arthur G., III
通讯作者：
Palmer, Arthur G., III
影响因子：
4.1
作者：
Cunningham, O;Gore, MG;Mantle, TJ
通讯作者：
Mantle, TJ
影响因子：
5.4
作者：
Kallberg, Yvonne;Oppermann, Udo;Persson, Bengt
通讯作者：
Persson, Bengt
影响因子：
8
作者：
Khavrutskii, Ilja V.;Price, Daniel J.;Brooks, Charles L., III
通讯作者：
Brooks, Charles L., III
影响因子：
7.5
作者：
Liebman, Howard A.
通讯作者：
Liebman, Howard A.