H. Loferer et H. Hennecke, EXPRESSION, PURIFICATION AND FUNCTIONAL-PROPERTIES OF A SOLUBLE FORM OF BRADYRHIZOBIUM-JAPONICUM TLPA, A THIOREDOXIN-LIKE PROTEIN, European journal of biochemistry, 223(2), 1994, pp. 339-344
The TlpA protein of Bradyrhizobium japonicum was previously identified
genetically as a membrane-anchored, periplasmic thioredoxin-like prot
ein. Here we describe the heterologous expression in Escherichia coli,
subsequent purification and biochemical characterization of TlpA. A s
oluble form of TlpA, which lacks its N-terminal membrane anchor, was o
verexpressed in E. coli and purified by a two-step procedure. Pure Tlp
A was shown to be a monomer in solution and was active in reducing the
disulfides of insulin and in reactivating reduced, denatured RNaseA.
Evidence is presented that two non-active-site cysteine residues form
an intramolecular disulfide bond, a feature that is not normally found
in other prokaryotic thioredoxins.