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Profiles of ILY, VLY and Sm-hPAF interaction with human CD59
Yuki Kawaguchi1, Atsushi Tabata, Hideaki Nagamune
1Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, 3500-3 Minamitamagaki-cho, Suzuka, Mie 513-8670, Japan. kohkura@suzuka-u.ac.jp
Background:
The molecular features of a new member of the bacterially -derived cytolysin family were examined. In particular, the interactive mechanisms of intermedilysin (ILY), vaginolysin (VLY), and Streptococcus mitis-derived human platelet aggregation factor (Sm-hPAF) with human CD59 (hCD59) were analyzed.
Materials And Methods:
Molecular models of VLY and Sm-hPAF were constructed based on X-ray data of ILY (protein data bank ID=1S3R), and their interactive profiles with hCD59 were examined using molecular simulation.
Results:
Non-binding (NB) energy between ILY and hCD59 was three orders of magnitude higher than the energy between VLY and hCD59. NB energy between Sm-hPAF and hCD59 was similar to that between VLY and hCD59.
Conclusion:
A hydrogen bond (ILY Arg432-hCD59 Glu76) was observed between ILY and hCD59, and a stronger interaction was formed by flexible adjustment between them.
Insights
Interactions between bacterial cytolysins and human CD59 were analyzed. Intermedilysin (ILY) showed weaker binding to human CD59 compared to vaginolysin (VLY) and Sm-hPAF.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Bacterial cytolysins are a family of toxins with diverse biological activities.
- Human CD59 is a complement regulatory protein that protects cells from complement-mediated lysis.
- Understanding the interaction between cytolysins and CD59 is crucial for elucidating cellular defense mechanisms.
Purpose of the Study:
- To investigate the molecular mechanisms underlying the interaction of intermedilysin (ILY), vaginolysin (VLY), and Streptococcus mitis-derived human platelet aggregation factor (Sm-hPAF) with human CD59 (hCD59).
- To compare the binding affinities and interaction profiles of these bacterial toxins with hCD59.
Main Methods:
- Construction of molecular models for VLY and Sm-hPAF based on existing ILY X-ray crystallographic data (PDB ID: 1S3R).
- Utilizing molecular simulation techniques to analyze the interactive profiles of VLY and Sm-hPAF with hCD59.
- Quantifying non-binding (NB) energy as a measure of interaction strength.
Main Results:
- The non-binding energy between ILY and hCD59 was found to be three orders of magnitude higher than that between VLY and hCD59, indicating significantly weaker binding of ILY.
- The non-binding energy between Sm-hPAF and hCD59 was comparable to the energy observed between VLY and hCD59, suggesting similar binding strengths for VLY and Sm-hPAF.
- A specific hydrogen bond interaction was identified between ILY residue Arg432 and hCD59 residue Glu76.
Conclusions:
- ILY exhibits a weaker interaction with hCD59 compared to VLY and Sm-hPAF.
- The interaction between ILY and hCD59 involves a hydrogen bond and is stabilized by flexible adjustments.
- These findings provide insights into the differential binding mechanisms of bacterial cytolysins to host cell proteins.
