PauA: a novel plasminogen activator from Streptococcus uberis

Chromosomal DNA from two geographically distinct isolates of Streptococcus uberis was used to clone the plasminogen activator in an active form in Escherichia coli. The cloned fragments from each strain contained four potential open reading frames (ORFs). That for the plasminogen activator encoded a protein of 286 amino acids (33.4 kDa) which is cleaved between residues 25 and 26 during secretion by S. uberis. The amino acid sequence of the mature protein showed only weak homology (23.5-28%) to streptokinase. The plasminogen activator gene, pauA, in S. uberis was located between two ORFs with high homology to the DNA mismatch repair genes, hexA and hexB, and not on a DNA fragment between the genes encoding an ATP binding cassette transporter protein (abc) and a protein involved in the formation and degradation of guanosine polyphosphates (rel) as is the case for streptokinase in other streptococci.