Figure 5. Naturally-occurring variants in Semaphorin-7A do not affect MTRAP binding.

(A) Representation of the dimeric Semaphorin-7A crystal structure showing the locations of the known naturally-occurring variants (PDB accession code 3NVQ [39]). The Ig-like domain is shown in yellow, the PSI domain in blue and the Sema domain in green. (B) Expression of naturally-occurring variants of Semaphorin-7A. All variants were expressed at the expected size as determined by Western blotting using streptavidin-HRP. (C) Naturally-occurring variants of Semaphorin-7A do not alter binding to MTRAP as shown by SPR. Serial dilutions of purified MTRAP were injected over Semaphorin-7A and the dissociation rate constant calculated and compared to each of the eight variants; for clarity, only E473V is shown here as a representative example. Dissociation rate constants (k _d) were calculated from two independent experiments and range between 0.050±0.003 s⁻¹ and 0.056±0.003 s⁻¹ (mean ± SEM) for all variants (Table S3).