Extensive small-angle X-ray scattering studies of blood coagulation factor VIIa reveal interdomain flexibility

TY - JOUR

T1 - Extensive small-angle X-ray scattering studies of blood coagulation factor VIIa reveal interdomain flexibility

AU - Mosbæk, Charlotte Rode

AU - Nolan, David

AU - Persson, Egon

AU - Svergun, Dmitri I

AU - Bukrinsky, Jens Thostrup

AU - Vestergaard, Bente

PY - 2010/11/16

Y1 - 2010/11/16

N2 - Blood coagulation factor VIIa (FVIIa) is used in the treatment of replacement therapy resistant hemophilia patients, and FVIIa is normally activated upon complex formation with tissue factor (TF), potentially in context with structural rearrangements. The solution behavior of uncomplexed FVIIa is important for understanding the mechanism of activation and for the stability and activity of the pharmaceutical product. However, crystal structures of FVIIa in complex with TF and of truncated free FVIIa reveal different overall conformations while previous small-angle scattering studies suggest FVIIa always to be fully extended in solution. Here, small-angle X-ray scattering analysis of multiple forms of FVIIa and TF under several experimental conditions elaborate extensively on the understanding of the solution behavior of FVIIa. We reveal significant FVIIa domain flexibility in solution, whereas TF has a well-defined conformation. Unspecific formation of dimers of FVIIa is also observed and varies with experimental conditions. In particular, active site-inhibited FVIIa displays a distinct solution behavior different from that of uninhibited FVIIa, which may reflect structural rearrangements causing resistance to activation, thereby emphasizing the connection between the distribution of different conformations of FVII and the mechanism of activation.

AB - Blood coagulation factor VIIa (FVIIa) is used in the treatment of replacement therapy resistant hemophilia patients, and FVIIa is normally activated upon complex formation with tissue factor (TF), potentially in context with structural rearrangements. The solution behavior of uncomplexed FVIIa is important for understanding the mechanism of activation and for the stability and activity of the pharmaceutical product. However, crystal structures of FVIIa in complex with TF and of truncated free FVIIa reveal different overall conformations while previous small-angle scattering studies suggest FVIIa always to be fully extended in solution. Here, small-angle X-ray scattering analysis of multiple forms of FVIIa and TF under several experimental conditions elaborate extensively on the understanding of the solution behavior of FVIIa. We reveal significant FVIIa domain flexibility in solution, whereas TF has a well-defined conformation. Unspecific formation of dimers of FVIIa is also observed and varies with experimental conditions. In particular, active site-inhibited FVIIa displays a distinct solution behavior different from that of uninhibited FVIIa, which may reflect structural rearrangements causing resistance to activation, thereby emphasizing the connection between the distribution of different conformations of FVII and the mechanism of activation.

KW - Former Faculty of Pharmaceutical Sciences

U2 - 10.1021/bi1011207

DO - 10.1021/bi1011207

M3 - Journal article

C2 - 20873866

SN - 0006-2960

VL - 49

SP - 9739

EP - 9745

JO - Biochemistry

JF - Biochemistry

IS - 45

ER -