Solution Structure of Tubuliform Spidroin N-Terminal Domain and Implications for pH Dependent Dimerization
The spidroin N-terminal domain (NT) is responsible for high solubility and pH-dependent assembly of spider silk proteins during storage and fiber formation, respectively. It forms a monomeric five-helix bundle at neutral pH and dimerizes at lowered pH, thereby firmly interconnecting the spidroins. M...
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Frontiers Media S.A.
2022-06-01
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| Series: | Frontiers in Molecular Biosciences |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmolb.2022.936887/full |
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| author | Megija Šede Jēkabs Fridmanis Martins Otikovs Jan Johansson Anna Rising Anna Rising Nina Kronqvist Kristaps Jaudzems Kristaps Jaudzems |
| author_facet | Megija Šede Jēkabs Fridmanis Martins Otikovs Jan Johansson Anna Rising Anna Rising Nina Kronqvist Kristaps Jaudzems Kristaps Jaudzems |
| author_sort | Megija Šede |
| collection | DOAJ |
| description | The spidroin N-terminal domain (NT) is responsible for high solubility and pH-dependent assembly of spider silk proteins during storage and fiber formation, respectively. It forms a monomeric five-helix bundle at neutral pH and dimerizes at lowered pH, thereby firmly interconnecting the spidroins. Mechanistic studies with the NTs from major ampullate, minor ampullate, and flagelliform spidroins (MaSp, MiSp, and FlSp) have shown that the pH dependency is conserved between different silk types, although the residues that mediate this process can differ. Here we study the tubuliform spidroin (TuSp) NT from Argiope argentata, which lacks several well conserved residues involved in the dimerization of other NTs. We solve its structure at low pH revealing an antiparallel dimer of two five-α-helix bundles, which contrasts with a previously determined Nephila antipodiana TuSp NT monomer structure. Further, we study a set of mutants and find that the residues participating in the protonation events during dimerization are different from MaSp and MiSp NT. Charge reversal of one of these residues (R117 in TuSp) results in significantly altered electrostatic interactions between monomer subunits. Altogether, the structure and mutant studies suggest that TuSp NT monomers assemble by elimination of intramolecular repulsive charge interactions, which could lead to slight tilting of α-helices. |
| first_indexed | 2024-04-12T16:00:58Z |
| format | Article |
| id | doaj.art-f4058a6ac28b4096adb54c9e3563d646 |
| institution | Directory Open Access Journal |
| issn | 2296-889X |
| language | English |
| last_indexed | 2024-04-12T16:00:58Z |
| publishDate | 2022-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Molecular Biosciences |
| spelling | doaj.art-f4058a6ac28b4096adb54c9e3563d6462022-12-22T03:26:12ZengFrontiers Media S.A.Frontiers in Molecular Biosciences2296-889X2022-06-01910.3389/fmolb.2022.936887936887Solution Structure of Tubuliform Spidroin N-Terminal Domain and Implications for pH Dependent DimerizationMegija Šede0Jēkabs Fridmanis1Martins Otikovs2Jan Johansson3Anna Rising4Anna Rising5Nina Kronqvist6Kristaps Jaudzems7Kristaps Jaudzems8Department of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, LatviaDepartment of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, LatviaDepartment of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, LatviaDepartment of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, SwedenDepartment of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, SwedenDepartment of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Biosciences and Nutrition, Neo, Karolinska Institutet, Huddinge, SwedenDepartment of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, LatviaFaculty of Chemistry, University of Latvia, Riga, LatviaThe spidroin N-terminal domain (NT) is responsible for high solubility and pH-dependent assembly of spider silk proteins during storage and fiber formation, respectively. It forms a monomeric five-helix bundle at neutral pH and dimerizes at lowered pH, thereby firmly interconnecting the spidroins. Mechanistic studies with the NTs from major ampullate, minor ampullate, and flagelliform spidroins (MaSp, MiSp, and FlSp) have shown that the pH dependency is conserved between different silk types, although the residues that mediate this process can differ. Here we study the tubuliform spidroin (TuSp) NT from Argiope argentata, which lacks several well conserved residues involved in the dimerization of other NTs. We solve its structure at low pH revealing an antiparallel dimer of two five-α-helix bundles, which contrasts with a previously determined Nephila antipodiana TuSp NT monomer structure. Further, we study a set of mutants and find that the residues participating in the protonation events during dimerization are different from MaSp and MiSp NT. Charge reversal of one of these residues (R117 in TuSp) results in significantly altered electrostatic interactions between monomer subunits. Altogether, the structure and mutant studies suggest that TuSp NT monomers assemble by elimination of intramolecular repulsive charge interactions, which could lead to slight tilting of α-helices.https://www.frontiersin.org/articles/10.3389/fmolb.2022.936887/fullspider silktubuliform spidroinN-terminal domainNMR structuredimerization mechanism |
| spellingShingle | Megija Šede Jēkabs Fridmanis Martins Otikovs Jan Johansson Anna Rising Anna Rising Nina Kronqvist Kristaps Jaudzems Kristaps Jaudzems Solution Structure of Tubuliform Spidroin N-Terminal Domain and Implications for pH Dependent Dimerization Frontiers in Molecular Biosciences spider silk tubuliform spidroin N-terminal domain NMR structure dimerization mechanism |
| title | Solution Structure of Tubuliform Spidroin N-Terminal Domain and Implications for pH Dependent Dimerization |
| title_full | Solution Structure of Tubuliform Spidroin N-Terminal Domain and Implications for pH Dependent Dimerization |
| title_fullStr | Solution Structure of Tubuliform Spidroin N-Terminal Domain and Implications for pH Dependent Dimerization |
| title_full_unstemmed | Solution Structure of Tubuliform Spidroin N-Terminal Domain and Implications for pH Dependent Dimerization |
| title_short | Solution Structure of Tubuliform Spidroin N-Terminal Domain and Implications for pH Dependent Dimerization |
| title_sort | solution structure of tubuliform spidroin n terminal domain and implications for ph dependent dimerization |
| topic | spider silk tubuliform spidroin N-terminal domain NMR structure dimerization mechanism |
| url | https://www.frontiersin.org/articles/10.3389/fmolb.2022.936887/full |
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