1apq: STRUCTURE OF THE EGF-LIKE MODULE OF HUMAN C1R, NMR, 19 STRUCTURES
1gpz: THE CRYSTAL STRUCTURE OF THE ZYMOGEN CATALYTIC DOMAIN OF COMPLEMENT PROTEASE C1R
1md7: Monomeric structure of the zymogen of complement protease C1r
1md8: Monomeric structure of the active catalytic domain of complement protease C1r