Possible arrangement of the five domains in human complement factor I as determined by a combination of X-ray and neutron scattering and homology modeling

The human complement factor I is a plasma serine protease that contains five domains consisting of One factor I-membrane attack complex domain, one CD5 domain, two low-density lipoprotein receptor domains and one serine protease domain. Factor one is essential in the regulation of complement. X-ray and neutron scattering were undertaken to determine the arrangement of these domain on complement factor I derived from human plasma.