Figure 2

PYST-A proteins predicted to be involved in lipid binding and transfer. (A) Predicted Bet v1-like superfamily domain (SSF55961, in red) in selected pyst-a gene family members from six Plasmodium species. Hmmer3 E-values shown in parentheses. (B) I-TASSER predicted homology model (C-score = −1.22) of the single P. falciparum pyst-a gene family member PF14_0604 (left) next to crystal structure of steroidogenic acute regulatory-related lipid transfer (START) domain-containing human protein MLN64 (PDB entry 1EM2; right). Predicted alpha helices and beta strands of PF14_0604 highlighted in blue and green, respectively. Note the overall high similarity between the two structures (TM-score = 0.724; RMSD = 1.71) (C) Protein sequence alignment obtained by threading PF14_0604 onto 1EM2 using MUSTER. Percent sequence identity (PID) of structurally aligned residues is 12.5% over 78% of PF14_0604 sequence length. Secondary structure (SS) elements colored according to structural model in B. Identical and similar amino acids colored in black and gray, respectively. Sequence and structural similarity suggest a potential role of the pyst-a gene family in lipid binding and transfer.