Fig. 1
Expression and Purification of target recombinant proteins in L. lactis. a Left panel: Schematic representation for cloning and expression of target recombinant proteins from P. falciparum antigens without (i) and with (ii) carrier fusion protein; Right panel: Classification of the target recombinant proteins based on their cysteine content (constructs containing two or more cysteine residues are classified as cysteine-rich proteins) and the overall success rates for production of target recombinant proteins by the respective L. lactis expression clones using strategy (i) or (ii). b Expression and purification of recombinant cMSP33D7 (a representative recombinant protein which does not contain cysteine residues and expressed successfully in L. lactis without carrier fusion protein); Left panel: Coomassie blue-stained non-reducing SDS-PAGE analysis showing purification of recombinant cMSP33D7protein secreted in L. lactis culture supernatant; Lane 1: raw culture supernatant, lane 2: Ni+-NTA purified cMSP33D7; lane 3: Ion-exchange purified cMSP33D7; Right panel: Western Blot analysis of recombinant cMSP33D7 using anti-His antibody. c Expression and purification of recombinant R0-MSPDBL2 (a representative cysteine-rich recombinant protein and which was expressed successfully in L. lactis with GLURP-R0 as a carrier fusion protein); Left panel: Coomassie blue-stained non-reducing SDS-PAGE analysis showing purification of recombinant R0-MSPDBL2 protein secreted in L. lactis culture supernatant; Middle panel: Western blot analysis of recombinant R0-MSPDBL2 using anti-His antibody; and Right panel: Western blot analysis of recombinant R0-MSPDBL2 using anti-GLURP-R0 antibody; Lane 1: raw culture supernatant; lane 2: Affinity purified R0-MSPDBL2 recombinant protein; lane 3: TEV cleavage of recombinant R0-MSPDBL2 and SDS-PAGE separation of R0 and MSPDBL2 fragments; Lane 4: Ion-exchange chromatography separates cleaved R0 carrier protein after TEV protease cleavage and Lane 5: Purified recombinant MSPDBL2 obtained after TEV cleavage and ion-exchange chromatography. The arrow-heads indicate positions of cMSP33D7 and MSPDBL2 recombinant proteins in respective panels. Numbers shown on the left hand side of the gel pictures represent positions of protein molecular weight markers in kDa