Diversified Structural Basis of a Conserved Molecular Mechanism for pH‐Dependent Dimerization in Spider Silk N‐Terminal Domains |
| |
| Authors: | Martins Otikovs Dr Gefei Chen Kerstin Nordling Dr Michael Landreh Prof Dr Qing Meng Dr Hans Jörnvall Dr Nina Kronqvist Dr Anna Rising Prof Dr Jan Johansson Dr Kristaps Jaudzems |
| |
| Affiliation: | 1. Latvian Institute of Organic Synthesis, Aizkraukles 21, LV‐1006 Riga (Latvia);2. Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Karolinska Institutet, Novum, 141 57 Huddinge (Sweden);3. Institute of Biological Sciences and Biotechnology, Donghua University, 201620 Shanghai (China);4. Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm (Sweden);5. Present address: Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 5QY (UK);6. Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, The Biomedical Centre, Box 575, 751 23 Uppsala (Sweden);7. Institute of Mathematics and Natural Sciences, Tallinn University, Narva mnt 25, 101 20 Tallinn (Estonia) |
| |
| Abstract: | Conversion of spider silk proteins from soluble dope to insoluble fibers involves pH‐dependent dimerization of the N‐terminal domain (NT). This conversion is tightly regulated to prevent premature precipitation and enable rapid silk formation at the end of the duct. Three glutamic acid residues that mediate this process in the NT from Euprosthenops australis major ampullate spidroin 1 are well conserved among spidroins. However, NTs of minor ampullate spidroins from several species, including Araneus ventricosus (AvMiSp NT), lack one of the glutamic acids. Here we investigate the pH‐dependent structural changes of AvMiSp NT, revealing that it uses the same mechanism but involves a non‐conserved glutamic acid residue instead. Homology modeling of the structures of other MiSp NTs suggests that these harbor different compensatory residues. This indicates that, despite sequence variations, the molecular mechanism underlying pH‐dependent dimerization of NT is conserved among different silk types. |
| |
| Keywords: | NMR structure pH sensitivity protein conformation spidroins |
|
|
