Plasmin(ogen)-binding alpha-enolase from Streptococcus pneumoniae: crystal structure and evaluation of plasmin(ogen)-binding sites.
Alpha-enolases are ubiquitous cytoplasmic, glycolytic enzymes. In pathogenic bacteria, alpha-enolase doubles as a surface-displayed plasmin(ogen)-binder supporting virulence. The plasmin(ogen)-binding site was initially traced to the two C-terminal lysine residues. More recently, an internal nine-amino acid motif comprising residues 248 to 256 was identified with this function. We report the crystal structure of alpha-enolase from Streptococcus pneumoniae at 2.0A resolution, the first structure both of a plasminogen-binding and of an octameric alpha-enolase. While the dimer is structurally similar to other alpha-enolases, the octamer places the C-terminal lysine residues in an inaccessible, inter-dimer groove restricting the C-terminal lysine residues to a role in folding and oligomerization. The nine residue plasminogen-binding motif, by contrast, is exposed on the octamer surface revealing this as the primary site of interaction between alpha-enolase and plasminogen.
Division of Structural Biology, GBF-German Research Center for Biotechnology, Mascheroder Weg 1, 38124 Braunschweig, Germany.
Stefanie
S
Ehinger
Wolf-Dieter
WD
Schubert
Simone
S
Bergmann
Sven
S
Hammerschmidt
Dirk W
DW
Heinz
D001224:Aspartic Acid / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D010751:Phosphopyruvate Hydratase / Q000737:chemistry* / Q000378:metabolism; D010958:Plasminogen / Q000378:metabolism*; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D013296:Streptococcus pneumoniae / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism
D001224:Aspartic Acid; D018698:Glutamic Acid; D010958:Plasminogen; D010751:Phosphopyruvate Hydratase; D008274:Magnesium