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Parsing redox potentials of five ferredoxins found within Thermotoga maritima
Author(s) -
Maiocco Stephanie J.,
Arcinas Arthur J.,
Booker Squire J.,
Elliott Sean J.
Publication year - 2019
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.3547
Subject(s) - thermotoga maritima , ferredoxin , redox , chemistry , enzyme , sulfur , iron–sulfur cluster , cluster (spacecraft) , dna , crystallography , stereochemistry , biochemistry , inorganic chemistry , computer science , organic chemistry , escherichia coli , programming language , gene
Most organisms contain multiple soluble protein‐based redox carriers such as members of the ferredoxin (Fd) family, that contain one or more iron–sulfur clusters. The potential redundancy of Fd proteins is poorly understood, particularly in connection to the ability of Fd proteins to deliver reducing equivalents to members of the “radical SAM,” or S ‐adenosylmethionine radical enzyme (ARE) superfamily, where the activity of all known AREs requires that an essential iron–sulfur cluster bound by the enzyme be reduced to the catalytically relevant [Fe 4 S 4 ] 1+ oxidation state. As it is still unclear whether a single Fd in a given organism is specific to individual redox partners, we have examined the five Fd proteins found within Thermotoga maritima via direct electrochemistry, to compare them in a side‐by‐side fashion for the first time. While a single [Fe 4 S 4 ]‐cluster bearing Fd (TM0927) has a potential of −420 mV, the other four 2x[Fe 4 S 4 ]‐bearing Fds (TM1175, TM1289, TM1533, and TM1815) have potentials that vary significantly, including cases where the two clusters of the same Fd are essentially coincident (e.g., TM1175) and those where the potentials are well separate (TM1815).