Comparison of amino acid regions forming [4Fe-4S] clusters in the SplB amino acid sequences from Bacillus anthracis (B.an), B. amyloliquefaciens (B.am), B. stearothermophilus (B.st), B. subtilis (B.su),Clostridium acetobutylicum (C.ac), and C. difficile (C.di) with the [4Fe-4S] clusters of: the activating subunits of ribonucleotide reductase (NrdG) and pyruvate-formate lyase (Act) from Escherichia coli (E.co), phage T4 (T4), andHaemophilus influenzae (H.in) and the [4Fe-4S] clusters from lysine-2,3-aminomutase (KamA) from Clostridium subterminale (C.su), biotin synthase (BioB) from B. subtilis, and the probable lipoic acid synthase (YutB) fromB. subtilis. Comparison of amino acid regions forming [4Fe-4S] clusters in the SplB amino acid sequences from Bacillus anthracis (B.an), B. amyloliquefaciens (B.am), B. stearothermophilus (B.st), B. subtilis (B.su),Clostridium acetobutylicum (C.ac), and C. difficile (C.di) with the [4Fe-4S] clusters of: the activating subunits of ribonucleotide reductase (NrdG) and pyruvate-formate lyase (Act) from Escherichia coli (E.co), phage T4 (T4), andHaemophilus influenzae (H.in) and the [4Fe-4S] clusters from lysine-2,3-aminomutase (KamA) from Clostridium subterminale (C.su), biotin synthase (BioB) from B. subtilis, and the probable lipoic acid synthase (YutB) fromB. subtilis. Highly conserved residues are in bold, and invariant cysteines are marked with an asterisk. Wayne L. Nicholson et al. Microbiol. Mol. Biol. Rev. 2000; doi:10.1128/MMBR.64.3.548-572.2000