FIG 1.

Endothelial binding is localized to the lipocalin fold-containing domain of Tp0751. (A) Schematic of Tp0751 primary sequence, including the signal peptide (SP) (black box) (M1 to S23 [M1–S23]), defined secondary structure elements (V99–H228) (gray box) (45), and N-terminal truncations corresponding to the mature lipoprotein (blue), the lipocalin fold-containing domain with the N-terminal helix (green), or the lipocalin fold-containing domain (purple). (B and C) Plate-based binding assays evaluated attachment of recombinant Tp0751 N-terminal truncations and the negative-control Tp0327 (I23–S172) to human umbilical vein endothelial cells (HUVECs) (B) and human microvascular dermal endothelial cells (HMVECd) (C). Proteins were added in equimolar concentration (25 μM), and results are presented as means plus standard errors of the means (SEM) (error bars) from three independent experiments performed in triplicate. Statistical analysis was performed by Student’s two-tailed t test comparing endothelial binding of Tp0751 N-terminal truncations to Tp0327 (I23–S172) (***, P < 0.001).