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Binding of the kringle-2 domain of human plasminogen to streptococcal PAM-type M-protein causes dissociation of PAM dimers
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  • Olawole Ayinuola,
  • Yetunde Ayinuola,
  • Cunjia Qiu,
  • Shaun Lee,
  • Victoria Ploplis,
  • Francis Castellino
Olawole Ayinuola
University of Notre Dame

Corresponding Author:[email protected]

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Yetunde Ayinuola
University of Notre Dame
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Cunjia Qiu
University of Notre Dame
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Shaun Lee
University of Notre Dame
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Victoria Ploplis
University of Notre Dame
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Francis Castellino
University of Notre Dame
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Abstract

M-protein (PAM) largely contributes to the pathogenesis of Pattern D Group A Streptococcus pyogenes (GAS). However, the mechanism of complex formation is unknown. In a system consisting of a Class II PAM from Pattern D GAS isolate NS88.2 (PAMNS88.2), with one K2hPg binding a-repeat in its A-domain, we employed biophysical techniques to analyze the mechanism of the K2hPg/PAMNS88.2 interaction. We show that apo-PAMNS88.2 is a coiled-coil homodimer (M.Wt. ~80 kDa) at 4°C - 25°C, and is monomeric (M.Wt. ~40 kDa) at 37°C, demonstrating a temperature-dependent dissociation of PAMNS88.2 over a narrow temperature range. PAMNS88.2 displayed a single tight binding site for K2hPg at 4°C, which progressively increased at 25°C through 37°C. We isolated the K2hPg/PAMNS88.2 complexes at 4°C, 25°C, and 37°C and found molecular weights of ~50 kDa at each temperature, corresponding to a 1:1 (m:m) K2hPg/PAMNS88.2 monomer complex. hPg activation experiments by streptokinase demonstrated that the hPg/PAMNS88.2 monomer complexes are fully functional. The data show that PAM dimers dissociate into functional monomers at physiological temperatures or when presented with the active hPg module (K2hPg) showing that PAM is a functional monomer at 37°C.
07 Sep 2021Submitted to MicrobiologyOpen
09 Sep 2021Submission Checks Completed
09 Sep 2021Assigned to Editor
14 Sep 2021Reviewer(s) Assigned
19 Oct 2021Review(s) Completed, Editorial Evaluation Pending
21 Oct 2021Editorial Decision: Revise Minor
25 Oct 20211st Revision Received
25 Oct 2021Submission Checks Completed
25 Oct 2021Assigned to Editor
25 Oct 2021Review(s) Completed, Editorial Evaluation Pending
25 Oct 2021Reviewer(s) Assigned
02 Nov 2021Editorial Decision: Revise Minor
03 Nov 20212nd Revision Received
03 Nov 2021Submission Checks Completed
03 Nov 2021Assigned to Editor
03 Nov 2021Review(s) Completed, Editorial Evaluation Pending
03 Nov 2021Editorial Decision: Accept
Nov 2021Published in MicrobiologyOpen volume 10 issue 6. 10.1002/mbo3.1252