Structure and binding determinants of the recombinant kringle-2 domain of human plasminogen to an internal peptide from a group A Streptococcal surface protein 1 1Edited by R. Huber

The Maintenance of High Affinity Plasminogen Binding by Group A Streptococcal Plasminogen-binding M-like Protein Is Mediated by Arginine and Histidine Residues within the a1 and a2 Repeat Domains

“…However, the spectra for all ␣-helical proteins are not identical due to the small effect of non-aromatic side chains on the rotary strength of the peptide bond and occasional helix distortions (24). It has also been shown that the ␣-helical structure of the peptide VEK-30, representative of the a1 repeat of PAM, increases from 25% to 75% upon binding to kringle 2 of plasminogen (16). It is possible that a similar structural shift could occur in the full-length PAM protein.…”

“…Early reports suggested that Lys 98 of the a1 repeat contributed the majority of the plasminogen binding ability of PAM (14). However, studies involving a polypeptide designated VEK-30 and a recombinant kringle 2 modified to contain a high affinity lysine binding site, highlighted a potential role for internal His 102 , Arg 101 , and Glu 104 residues within the a1 repeat in this interaction (15,16). VEK-30 is composed of the six residues preceding the a1 repeat, the entire a1 repeat, together with the first ten residues of the a2 repeat of PAM (17).…”

Plasminogen Substrate Recognition by the Streptokinase-Plasminogen Catalytic Complex Is Facilitated by Arg253, Lys256, and Lys257 in the Streptokinase β-Domain and Kringle 5 of the Substrate

“…Given the general specificity of Pg kringles for COOH-terminal Lys residues and zwitterionic ligands, such as 6-AHA, and the internal sequence of the 250-loop, it appeared possible that a pseudolysine motif on SK was involved. In the binding of a 30-residue peptide from plasminogen binding Group A streptococcal M-like protein (PAM), VEK-30, to K2 of Pg, Castellino and co-workers (41,42) showed by crystallography and mutagenesis that residues with cationic (Arg and His) and anionic side chains (Glu) arranged spatially on a helix constituted a pseudolysine structure similar to 6-AHA that binds specifically to the LBS of K2. Additional evidence for pseudolysine structures in Pg binding comes from studies of ␣-enolase from Streptococcus pneumoniae, which has a 9-residue internal binding site for Pg containing essential basic (two Lys residues) and acidic (Asp and Glu residues) located on a surface loop (43,44).…”

Divergence in the Plasminogen-binding Group A Streptococcal M Protein Family

“…Although the binding characteristics of fragments representing different a1/a2 repeat sequences have been investigated previously (13,15), the functional characteristics of M proteins, including fibrinogen and plasminogen binding, may depend largely on their overall structure (36,40), highlighting the importance of using full-length protein in functional studies. Binding dissociation constants for the interaction of PAM variants and biotinylated plasminogen were within the same range as reported previously for PAM and plasminogen binding M proteins of groups C and G streptococci (2,12,35).…”

“…PAM lacks the typical C-terminal lysine residues of many plasminogen receptors (3,10,11). Rather, internal lysine residues in the a1/a2 repeat regions of PAM (Lys 98 and Lys 111 ), along with internal His 102 , Arg 101 , and Glu 104 residues in a1, mediate binding to kringle 2 of plasminogen (12)(13)(14)(15).…”