5IZ2

Crystal structure of the N. clavipes spidroin NTD at pH 6.5

5IZ2 の概要

• エントリーDOI: 10.2210/pdb5iz2/pdb
• 分子名称: Major ampullate spidroin 1A, Major ampullate spidroin 1A (Partial C-terminus) (3 entities in total)
• 機能のキーワード: spidroin, major ampullate, homodimer, structural protein
• 由来する生物種: Nephila clavipes (Golden silk orbweaver); 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 30276.37

構造登録者

Atkison, J.H.,Olsen, S.K. (登録日: 2016-03-24, 公開日: 2016-07-27, 最終更新日: 2023-09-27)

主引用文献

Atkison, J.H.,Parnham, S.,Marcotte, W.R.,Olsen, S.K.
Crystal Structure of the Nephila clavipes Major Ampullate Spidroin 1A N-terminal Domain Reveals Plasticity at the Dimer Interface.
J.Biol.Chem., 291:19006-19017, 2016

PubMed Abstract: Spider dragline silk is a natural polymer harboring unique physical and biochemical properties that make it an ideal biomaterial. Artificial silk production requires an understanding of the in vivo mechanisms spiders use to convert soluble proteins, called spidroins, into insoluble fibers. Controlled dimerization of the spidroin N-terminal domain (NTD) is crucial to this process. Here, we report the crystal structure of the Nephila clavipes major ampullate spidroin NTD dimer. Comparison of our N. clavipes NTD structure with previously determined Euprosthenops australis NTD structures reveals subtle conformational alterations that lead to differences in how the subunits are arranged at the dimer interface. We observe a subset of contacts that are specific to each ortholog, as well as a substantial increase in asymmetry in the interactions observed at the N. clavipes NTD dimer interface. These asymmetric interactions include novel intermolecular salt bridges that provide new insights into the mechanism of NTD dimerization. We also observe a unique intramolecular "handshake" interaction between two conserved acidic residues that our data suggest adds an additional layer of complexity to the pH-sensitive relay mechanism for NTD dimerization. The results of a panel of tryptophan fluorescence dimerization assays probing the importance of these interactions support our structural observations. Based on our findings, we propose that conformational selectivity and plasticity at the NTD dimer interface play a role in the pH-dependent transition of the NTD from monomer to stably associated dimer as the spidroin progresses through the silk extrusion duct.

PubMed: 27445329
DOI: 10.1074/jbc.M116.736710

実験手法

X-RAY DIFFRACTION (2.02 Å)