期刊
CHEMBIOCHEM
卷 22, 期 7, 页码 1285-1291出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/cbic.202000768
关键词
biocatalytic promiscuity; cytochrome c; Kemp elimination; membrane-mimetic system; protein unfolding
资金
- Science and Engineering Research Board (SERB), New Delhi [SRG/2019/000365]
- IISER Mohali
- Centre for Protein Science Design and Engineering (CPSDE), IISERM)
Cytochrome c displays proficient proton-transfer catalytic property on self-organized systems, enhancing Kemp elimination by approximately 750-fold. This catalytic property is mainly facilitated by His18 for proton abstraction, promoting the KE catalysis through E2 pathway. Additionally, under reducing conditions, the redox pathway becomes predominant, showing almost 750-fold enhanced catalysis by cyt c compared to aqueous buffer.
Evolutionarily elderly proteins commonly feature greater catalytic promiscuity. Cytochrome c is among the first set of proteins in evolution to have known prospects in electron transport and peroxidative properties. Here, we report that cyt c is also a proficient proton-transfer catalyst and enhances the Kemp elimination (KE; model reaction to show proton transfer catalytic property) by similar to 750-fold on self-organized systems like micelles and vesicles. The self-organized systems mimic the mitochondrial environment in vitro for cyt c. Using an array of biophysical and biochemical mutational assays, both acid-base and redox mechanistic pathways have been explored. The histidine moiety close to hemin group (His18) is mainly responsible for proton abstraction to promote the concerted E2 pathway for KE catalysis when cyt c is in its oxidized form; this has also been confirmed by a H18A mutant of cyt c. However, the redox pathway is predominant under reducing conditions in the presence of dithiothreitol over the pH range 6-7.4. Interestingly, we found almost 750-fold enhanced KE catalysis by cyt c compared to aqueous buffer. Overall, in addition to providing mechanistic insights, the data reveal an unprecedented catalytic property of cyt c that could be of high importance in an evolutionary perspective considering its role in delineating the phylogenic tree and also towards generating programmable designer biocatalysts.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据