J. Biol. Chem., Vol. 268, Issue 34, 25417-25424, 12, 1993
PAM, a novel plasminogen-binding protein from Streptococcus pyogenes
A Berge and U Sjobring
Department of Medical and Physiological Chemistry, Lund University, Sweden.
The ability of group A streptococci to bind human plasminogen and plasmin
has attracted interest, because it could provide the bacteria with a
mechanism for invasion. M or M-like proteins account for the binding of
several plasma proteins to group A streptococci. To investigate whether M
or M-like proteins were responsible for the binding of plasminogen to group
A streptococci, acid-extracted material from a type M53 streptococcal
isolate was tested for its ability to bind plasminogen. Indeed, a 42-kDa
plasminogen-binding protein was solubilized. Two oligonucleotides
homologous with conserved sequences in known M protein genes were used as
primers in the polymerase chain reaction, with chromosomal DNA from the M53
isolate. When cloned and expressed in Escherichia coli, a resulting
fragment encoded a 43-kDa plasminogen-binding protein. Nucleotide sequence
determination of the gene fragment revealed an open reading frame encoding
a polypeptide of 43,580 Da, which matched the amino-terminal amino acid
sequence of the plasminogen-binding protein extracted from M53
streptococci. The DNA sequence data also proved the relationship of the
encoded protein, named PAM, to the M proteins. The plasminogen-binding
domain was mapped to the amino-terminal third of PAM. Plasminogen absorbed
by M53 streptococci or by immobilized PAM could be activated by
streptokinase. The results provide further evidence of the diversity of the
M protein family and suggest a new mechanism whereby these proteins
contribute to the virulence of group A streptococci.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
