Fig 5.

Biophysical and computational analyses of the structure of rMTRAP. (A) Far-UV analysis of rMTRAP and rCSP by circular dichroism in an aqueous solution. The ellipticity (degrees cm²/dmol) was plotted as a function of wavelength (nm). Raw data measured in millidegrees was converted into ellipticity (degrees cm²/dmol). Spectra were obtained at 20°C. (B) Alignment of MTRAP TSR domains from Plasmodium species with human TSP-1 TSR domains. Regions restrained to the coordinates of HsTSP-1 during homology modeling are indicated by yellow boxes. Conserved residues predicted to participate in the formation of the stacked TSR core are boxed in cyan, and nonconserved arginines in the C-terminal MTRAP TSR domains predicted to participate in stacking are boxed in periwinkle. The glutamic and aspartic acid residues predicted to hydrogen bond to the conserved central stacked arginine are boxed in light red. The secondary structure and disulfide linkages of HsTSP-1 are shown below the alignment. The predicted additional group 2 disulfide linkages of MTRAP TSR are indicated above the alignment. Organism codes and NCBI locus tags are as follows: Pf, Plasmodium falciparum, PF10_0281; Pv, Plasmodium vivax, PVX-111290; Pk, Plasmodium knowlesi, PKH_061300; Pb, Plasmodium berghei, PB000355.03.0; Pc, Plasmodium chabaudi, PC000113.04.0; Hs, Homo sapiens, THBS1. (C) Homology models of the first and second predicted TSR domains of MTRAP and the crystal structure of TSR2 of HsTSP-1. Regions predicted to align between the MTRAP TSRs and the HsTSP-1 TSRs are shown in yellow. Conserved residues participating in the stacked core and the hydrogen-bonded glutamic acid of the TSR domains are shown as cyan sticks. Disulfide linkages are shown in a stick representation.