Exploring the Structure

As seen in PDB entry 1dan, factor VII embraces tissue factor, contacting the entire length of the molecule. Factor VII has four domains strung together with flexible linkers. At the bottom is the GLA domain, which has nine modified glutamic acids, labeled CGU in the PDB structure file. These modified amino acids have an extra carboxylic acid group that traps calcium ions. The ions interact with the membrane surface, helping factor VII find tissue factor. The uppermost domain of factor VII is a protein- cutting enzyme that will make the break in the factor X. This domain looks very much like other serine proteases such as trypsin and thrombin. In the middle are two small domains that assist with the recognition of tissue factor. The small molecule in green is an inhibitor that blocks the active site and thus acts as an anticoagulant that stops blood clotting.

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A list of 'tissue factor' related entries in the PDB as determined by a keyword search on March 03, 2006 is available here. For a general reference on the molecules of blood clotting, click here.