Fig. 4

Structural modeling of patient SLIT2 mutation: a Diagram of SLIT2 domains. The SLIT2 protein is processed into two fragments, SLIT2-N and SLIT2-C. The approximate site of proteolytic cleavage is shown. b Structural model of the full-length human SLIT2 protein generated through a domain assembly approach (see Additional file 1). The p.D1407G mutation is located in the SLIT-C region in the EGF-like domain 8. c Multiple sequence alignment of SLIT2 EGF-like 8 domains from multiple species reveals conservation of the D1407 residue. EGF-like domains contain six conserved cysteine residues (highlighted by the blue outline) that form three disulfide bridges that provide structural rigidity to the domain. d The D1407 residue is located adjacent to a disulfide bridge which would restrain the residue. Substitution with glycine would lead to more conformational flexibility at this site and potentially destabilize the domain by altering disulfide bond formation. e In addition to destabilizing the EGF-like domain, the p.D1407G mutation disrupts a negative charge at this site. Electrostatic surface potentials calculated using APBS software highlight the loss of negative charge in this region, which may be critical for maintaining interactions with SLIT2-C binding partners