Characterization of two transketolases encoded on the chromosome and the plasmid pBM19 of the facultative ribulose monophosphate cycle methylotroph Bacillus methanolicus.

ABSTRACT:

Background

Transketolase (TKT) is a key enzyme of the pentose phosphate pathway (PPP), the Calvin cycle and the ribulose monophosphate (RuMP) cycle. Bacillus methanolicus is a facultative RuMP pathway methylotroph. B. methanolicus MGA3 harbors two genes putatively coding for TKTs; one located on the chromosome (tkt(C)) and one located on the natural occurring plasmid pBM19 (tkt(P)).

Results

Both enzymes were produced in recombinant Escherichia coli, purified and shown to share similar biochemical parameters in vitro. They were found to be active as homotetramers and require thiamine pyrophosphate for catalytic activity. The inactive apoform of the TKTs, yielded by dialysis against buffer containing 10 mM EDTA, could be reconstituted most efficiently with Mn(2+) and Mg(2+). B

SUBMITTER: Markert B 

PROVIDER: S-EPMC3905653 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature