Isopropylthiogalactoside

pET-41a (+) vector expressing GST-Rad51 or pBad/His A vector expressing 6xHis-TCTP (Invitrogen) was transformed into BL21 E. coli, the transformed bacteria were cultured in LB medium until its optical density 600 nm reached to 1.0. Isopropylthiogalactoside or l-arabinose (Sigma-Aldrich) was added into the culture at a concentration of 0.2 mm and the desired expression of protein was inducted for 8 h at 30 °C. The bacteria were harvested by centrifugation and lysed by sonication. GST-Rad51 or 6xHis-TCTP protein was affinity purified by using glutathione or Ni-NTA magnetic beads (Thermo Fisher Scientific). Bound proteins were eluted with solution containing glutathione or imidazole and dialyzed against PBS buffer as the methods described in the user manual provided by the manufacturer.

The Isopropyl thiogalactoside (IPTG), 5-Bromo-4-chloro-indolyl-β-D galactopyranoside (X-Gal), Avicel, carboxy methyl cellulose (CMC) and antibiotic (ampicillin) were purchased from Sigma Aldrich (St. Louis, USA). The restriction and DNA modifying enzymes purchased from Fermentas (Lithuania USA). All other chemicals of analytical grade were being used in this study. The Thermotoga maritima (Tma) MSB8 strain was purchased from the American Type Culture Collection (ATCC, Parkville – USA), and was cultured in Thermotoga basal medium (TMB) with 0.5% glucose added (Jiang 2006 ). The host E. coli DH5α competent cells were obtained from Promega Corporation (Madison, WI, United States), whereas the pQE-30 vector was bought from QIAGEN products by Edificio Alba 28,290 Las Matas (Spain).