Semaphorins dimerization

Fig. 9. Non-covalent semaphorin dimerization mediated by the sema domains. (A) The Sema3A-65K dimer in the asymmetric unit of the crystals. (B) The interacting sema domains in the Sema4D dimer viewed in the same orientation as in (A). The expansive dimerization interface (total buried area of approximately 3000 A ) is generated by the approximation of four protruding loops from each monomer. These loops, located at the top face of the fi propeller are also implicated in interactions with the semaphorin receptors.

Class 3 semaphorins are the best functionally characterized group. The presence of a sema domain and dimerization are the minimal... 

Klostermann, A., Lohrum, M., Adams, R. H., and Piischel, A. W. (1998). The chemo-repulsive activity of the axonal guidance signal semaphorin D requires dimerization./. Biol. Chem. 273, 7326-7331. 

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