Identification of a TeO32- reductase/mycothione reductase from Rhodococcus erythropolis PR4
Identification of a TeO32- reductase/mycothione reductase from Rhodococcus erythropolis PR4
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DOI：
10.1093/femsec/fiaa220
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发表时间：
2021-01-01
影响因子：
4.2
通讯作者：
Ackerson, Christopher J.
中科院分区：
文献类型：
--
作者：
Butz, Zachary J.;Hendricks, Alexander;Ackerson, Christopher J.
红平红球菌细菌，耐受正常致死浓度的Fe（II），Cu（II），AsO 32-，SeO 32-，TeO 32-，Cd（II）和Zn（II）的环境分离物进行了鉴定。在表征金属耐受性的分子基础，真菌还原酶（MTR）具有显着的选择性TeO 32-还原SeO 32-被确定。在等摩尔浓度的TeO 32-和SeO 32-中，酶促产物含有7倍过量的Te。该选择性是显著的，因为SeO 32-的标准还原电位比TeO 32-更有利于还原0.20 V。TeO 32-的酶的选择性随着测定pH值的增加而降低。同源建模的酶确定四个芳香族残基附近的活性位点，包括两个组氨酸残基，这是不存在于相关的SeO 32-偏好还原酶。的基础上更有利的π相互作用Te比Se和pH值的依赖性的选择性，Te的选择性部分归因于这些芳香族残基。所得的Te-0酶促产物类似于Te纳米线。
A Rhodococcus erythropolis bacterium that tolerates normally lethal concentrations of Fe(II), Cu(II), AsO32-, SeO32-, TeO32-, Cd(II) and Zn(II) was identified from an environmental isolate. In characterizing the molecular basis for metal tolerance, a mycothione reductase (Mtr) with remarkable selectivity for TeO32- reduction over SeO32 - was identified. In equimolar concentrations of TeO32- and SeO32-, the enzymatic product contains a 7-fold excess of Te. This selectivity is remarkable because the standard reduction potential of SeO32- is 0.20 V more favorable for reduction than TeO32-. Selectivity of the enzyme for TeO32- decreases with increasing assay pH. Homology modeling of the enzyme identifies four aromatic residues near the active site, including two histidine residues, that are not present in a related SeO32- preferring reductase. On the basis of more favorable pi-interactions for Te than for Se and the pH dependence of the selectivity, the Te-selectivity is attributed in part to these aromatic residues. The resulting Te-0 enzymatic product resembles Te nanowires.