Table S1.
Bacterial strains and plasmids
| Strain/plasmid | Relevant features; comments | Source |
| E. coli strains | ||
| DH5α | F– endAI recAl hsdRl7 (rK− mK−) deoR supE44 thi-J gyrA96 relA | Gibco-BRL |
| MG1655 (DE3) | F− (λDE3) ilvG rfb50 rph1 | James Imlay, University of Illinois, Urbana, IL |
| BL21 (DE3) | F– ompT hsdSB(rB–mB–) gal dcm rne131 (DE3) | Life Technologies |
| Plasmids | ||
| pACYCDuet-1 | Expression vector, T7 promoter, CamR | Novagen |
| pACYCDuet-1 FL SufB endo− | Mtu full-length sufb gene cloned into EcoRI/HindIII sites, with endonuclease mutations | |
| pACYC MIG-SufB | Mtu SufB intein flanked by short extein sequences (N-extein: ADEGSYVHYVEG; C-extein: CTAPIYKSDSLH) cloned into ClaI/SphI sites between MBP and GFP coding sequences in pACYCDuet-1 backbone, endonuclease mutations | This study |
| pACYC MIG-SufB C+1S | Site-directed mutagenesis of the pACYC MIG-SufB plasmid to mutate C+1 residue to S, endonuclease mutations | This study |
| pACYC MIG-RecA K-1P | Mtu minimized RecA intein flanked by short extein sequences (N-extein: RTRVKVVKNK; C-extein: CSPPFKQAEF) cloned into ClaI/SphI sites between MBP and GFP coding sequences in pACYCDuet-1 backbone, site directed mutagenesis carried out to mutate K-1 to P which inhibits splicing | This study |
| pACYC MIG-DnaB G-1F | Mtu DnaB intein flanked by short extein sequences (N-extein: PMLADLRESG; C-extein: SLEQDAD) cloned into ClaI/SphI sites between MBP and GFP coding sequences in pACYCDuet-1 backbone, site directed mutagenesis carried out to mutate G-1 to F which delays splicing | This study |
| pET30b | Cloning Vector | Novagen |
| pET30b/WT SufB Intein 4C/S | Four cysteines in endonuclease domain mutated to serine | This study |
| pET30b/C+1S SufB Intein 4C/S | Four cysteines in endonuclease domain mutated to serine | This study |