Abstract
BackgroundThe identity of the amino acid regions of factor VIII (FVIII) that contribute to factor IXa (FIXa) and von Willebrand factor (VWF) binding has not been fully resolved. Previously, we observed that replacing the FVIII C1 domain for the one of factor V (FV) markedly reduces VWF binding and cofactor function. Compared to the FV C1 domain, this implies that the FVIII C1 domain comprises unique surface‐exposed elements involved in VWF and FIXa interaction. ObjectiveThe aim of this study is to identify residues in the FVIII C1 domain that contribute to VWF and FIXa binding. MethodsStructures and primary sequences of FVIII and FV were compared to identify surface‐exposed residues unique to the FVIII C1 domain. The identified residues were replaced with alanine residues to identify their role in FIXa and VWF interaction. This role was assessed employing surface plasmon resonance analysis studies and enzyme kinetic assays. ResultsFive surface‐exposed hydrophobic residues unique to the FVIII C1 domain, ie, F2035, F2068, F2127, V2130, I2139 were identified. Functional analysis indicated that residues F2068, V2130, and especially F2127 contribute to VWF and/or FIXa interaction. Substitution into alanine of the also surface‐exposed V2125, which is spatially next to F2127, affected only VWF binding. ConclusionThe surface‐exposed hydrophobic residues in C1 domain contribute to cofactor function and VWF binding. These findings provide novel information on the fundamental role of the C1 domain in FVIII life cycle.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.