Iron-sulfur cluster engineering provides insight into the evolution of substrate specificity among sulfonucleotide reductases.
Iron-sulfur cluster engineering provides insight into the evolution of substrate specificity among sulfonucleotide reductases.
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DOI：
10.1021/cb200261n
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发表时间：
2012-02-17
影响因子：
4
通讯作者：
Carroll, Kate S.
中科院分区：
文献类型：
--
作者：
Bhave, Devayani P.;Hong, Jiyoung A.;Keller, Rebecca L.;Krebs, Carsten;Carroll, Kate S.
Assimilatory sulfate reduction supplies prototrophic organisms with reduced sulfur that is required for the biosynthesis of all sulfur-containing metabolites, including cysteine and methionine. The reduction of sulfate requires its activation via an ATP-dependent activation to form adenosine-5′-phosphosulfate (APS). Depending on the species, APS can be reduced directly to sulfite by APS reductase (APR) or undergo a second phosphorylation to yield 3′-phosphoadenosine-5′-phosphosulfate (PAPS), the substrate for PAPS reductase (PAPR). These essential enzymes have no human homolog, rendering them attractive targets for the development of novel antibacterial drugs. APR and PAPR share sequence and structure homology as well as a common catalytic mechanism, but the enzymes are distinguished by two features, namely, the amino acid sequence of the phosphate-binding loop (P-loop) and an iron-sulfur cofactor in APRs. Based on the crystal structures of APR and PAPR, two P-loop residues are proposed to determine substrate specificity; however, this hypothesis has not been tested. In contrast to this prevailing view, we report here that the P-loop motif has a modest effect on substrate discrimination. Instead, by means of metalloprotein engineering, spectroscopic and kinetic analyses, we demonstrate that the iron-sulfur cluster cofactor enhances APS reduction by nearly 1000-fold, thereby playing a pivotal role in substrate specificity and catalysis. These findings offer new insights into the evolution of this enzyme family, and extend the known functions of protein-bound iron-sulfur clusters.
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影响因子：
7.8
作者：
Booker, Squire J.
通讯作者：
Booker, Squire J.
影响因子：
4.6
作者：
Bhave DP;Han WG;Pazicni S;Penner-Hahn JE;Carroll KS;Noodleman L
通讯作者：
Noodleman L
影响因子：
5.6
作者：
Chartron, Justin;Carroll, Kate S.;Stout, C. David
通讯作者：
Stout, C. David
DOI：
10.1073/pnas.94.13.6635
发表时间：
1997-06-24
影响因子：
11.1
作者：
Coldren, CD;Hellinga, HW;Caradonna, JP
通讯作者：
Caradonna, JP
影响因子：
56.9
作者：
Masip, L;Pan, JL;Collet, JF
通讯作者：
Collet, JF