Effect of γ′ on the molecular structure of fibrin fibers over a range of thrombin concentrations. Fibrin was made with 1 mg/mL purified γA/γA (white bars) or γA/γ′ (black bars) fibrinogen, 2.5 mM CaCl2, and a range of thrombin concentrations. (A) Fibrin fiber radius. (B) Number of protofibrils within fibrin fibers. (C) Protein density of fibrin fibers. (D) Distance between protofibrils inside the fibrin fibers. (E) Cold field scanning electron images of γA/γA and (F) γA/γ′ fibrin fibers both produced with 1 mg/mL fibrinogen, 0.1 U/mL thrombin, and 10 mM CaCl2 (scale bars, 200 nm). (G) Polyacrylamide gel electrophoresis of fibrinogen. Lane 1, molecular marker (kDa); lane 2, γA/γA fibrinogen; lane 3, γA/γ′ fibrinogen; lane 4, human plasminogen-depleted IF-1 purified fibrinogen. The results represent the mean values ± SD, n = 3. Statistical significance, using a 2-way ANOVA, is denoted with ***P < .005 and ****P < .001 for comparison between γA/γA and γA/γ′ at each thrombin concentrations.
