Sandbox Reserved 1101: Difference between revisions

The dimerization of the spidroin by the NTD domain begins by a rearrangement of the five-helix bundle during the monomer to dimer transition. An acidification along the spinning duct results in a conformational change of the NTD. So, for the NTD dimerization, a lowering of pH from 7 to 6 is important.  Then, a subunit selects a partner with a complementary binding interface. When the NTD forms a dimer, its positive and negative poles are opposed, creating an environment conducive to salt bridges formation. Moreover, dimerization is really triggered and stabilized by protonation of some residues. Studies have also shown that a lowering more important of the pH stabilizes even more the dimer. The plasticity of the dimer interface could also be a factor of the conformational selection during transition from monomer to dimer or during the transition from loosely to stably dimer.