PAM, a novel plasminogen-binding protein from Streptococcus pyogenes

• Published in: The Journal of biological chemistry 1993-12, Vol.268 (34), p.25417-25424
• Main Authors: Berge, A, Sjöbring, U
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Aminocaproic Acid - pharmacology; Analytical, structural and metabolic biochemistry; Bacterial Proteins; Base Sequence; Binding and carrier proteins; Biological and medical sciences; Carrier Proteins - biosynthesis; Carrier Proteins - isolation & purification; Carrier Proteins - metabolism; Chromatography, Affinity; Cloning, Molecular; Escherichia coli - metabolism; Fibrinolysin - pharmacology; Fundamental and applied biological sciences. Psychology; Humans; Kinetics; Molecular Sequence Data; Plasmids; Plasminogen - metabolism; Protein Conformation; Protein Structure, Secondary; Proteins; Recombinant Proteins - biosynthesis; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Streptococcus pyogenes; Streptococcus pyogenes - genetics; Streptococcus pyogenes - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)74408-1

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.