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Factor XIII Activation Peptide Residues Play Important Roles in Stability, Activation, and Transglutaminase Activity
Rameesa D Syed Mohammed1, Lianay Gutierrez Luque1, Muriel C Maurer1
1Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, United States.
Biochemistry
|October 18, 2024
Summary
The study identified key amino acid residues in the factor XIII-A (FXIII-A) activation peptide (AP) crucial for protein stability and function. Specific mutations impact FXIII-A stability, thrombin activation, and transglutaminase activity.
Area of Science:
- Biochemistry
- Molecular Biology
- Protein Chemistry
Background:
- Factor XIII (FXIII) is a plasma transglutaminase essential for hemostasis.
- The FXIII-A subunit's activation peptide (AP) regulates its stability and activation.
- FXIII activation occurs proteolytically in plasma and non-proteolytically in the cytoplasm.
Purpose of the Study:
- To investigate the role of individual FXIII-A AP residues in protein stability.
- To determine the impact of AP mutations on thrombin-mediated activation.
- To assess the effect of AP variants on transglutaminase activity.
Main Methods:
- Expression of recombinant FXIII-A AP variants.
- SDS-PAGE to monitor thrombin hydrolysis of AP.
- Mass spectrometry and in-gel fluorescence assays for transglutaminase activity assessment.
Main Results:
- Mutations S19P, E23K, and D24V led to FXIII-A degradation, highlighting their role in stability.
- Mutation P36 abolished AP cleavage, preventing activation.
- Mutations N20S and P27L slowed thrombin activation.
- Most activatable variants showed similar cross-linking activity, but cytoplasmic FXIII-A° variants with proline loss had reduced activity.
Conclusions:
- Specific FXIII-A AP residues are critical for protein stability, activation, and transglutaminase function.
- Interactions between AP residues and other domains govern FXIII stability and activity.
- Understanding these interactions provides insights into FXIII regulation and function.
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