Cloning and expression in Escherichia coli of the 37-, 14-, and/or 16-kilodalton antigens genes from Rickettsia prowazekii strain E.

A gene bank of Rickettsia prowazekii strain E constructed in the phage vector lambda EMBL4 was screened for antigen production with anti-R. prowazekii serum. One of the immunoreactive clones, grown at 37 degrees C exhibited the expression of at least two antigens of molecular weight (M(r)) 37 kD and 14 kD. Subcloning and further analysis revealed that the antigens (polypeptides) of Mr 37, 14, and/or 16 kD apparently represent structural units of the 138 kD complex antigen. Assembly of the above mentioned polypeptides was found to be thermosensitive as it took place at 30 degrees C but not at 37 degrees C and resulted in an oligomeric structure of M(r) 138 kD. The nucleotide sequence of the gene coding for a precursor of the mature polypeptides of Mr 14 and/or 16 kD was determined.