The RhoGAP-related domain of Class III plant formins. Top – comparison of the experimentally characterized structure of the mammalian BH (BCR homology) Rho GAP domain from the chicken protein GRAF (GgGRAF, [PDB: 1F7C]) and a three-dimensional model of the RhoGAP domain of the Physcomitrella patens Class III formin Phypa7, constructed as described in Materials and Methods. Surface residues are colored using the standard "color by type" scheme of SwissModel, except of the conserved arginine in the arginine finger of GgGRAF (purple) and the corresponding serine of Phypa7 (orange), also marked by a circle. Less confidently predicted parts of the model are shown in pale colors. Bottom – a structure-based alignment of the RhoGAP domains of four Class III formins with four structurally characterized mammalian Rho or Rac GAPs (GgGRAF – see above, HsRacGAP – human Rac-specific GAP/beta-chimaerin [PDB: 1XA6], Hs p85 – human RhoGAP-like BH-domain from phosphoinositide 3-kinase p85 [PDB: 1PBW], Hs p50 – the GTPase-activating domain from human p50rhoGAP [PDB: 1RGP]). Amino acids coloring as in the three-dimensional model, positions conserved across all mammalian sequences in bold, the arginine finger or corresponding diverged residues inverted (white on a coloured background), another similarly diverged site (conserved Lys to Leu mutation in formin-derived sequences) is shown on a gray background.