2MFZ

NMR structure of C-terminal domain from A. ventricosus minor ampullate spidroin (MiSp)

2MFZ の概要

• エントリーDOI: 10.2210/pdb2mfz/pdb
• NMR情報: BMRB: 19579
• 分子名称: Minor ampullate spidroin (1 entity in total)
• 機能のキーワード: structural protein
• 由来する生物種: Araneus ventricosus (Orbweaver spider)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 23533.60

構造登録者

Otikovs, M.,Jaudzems, K.,Andersson, M.,Chen, G.,Landreh, M.,Nordling, K.,Kronqvist, N.,Westermark, P.,Jornvall, H.,Knight, S.,Ridderstrale, Y.,Holm, L.,Meng, Q.,Chesler, M.,Johansson, J.,Rising, A. (登録日: 2013-10-24, 公開日: 2014-08-20, 最終更新日: 2024-05-01)

主引用文献

Andersson, M.,Chen, G.,Otikovs, M.,Landreh, M.,Nordling, K.,Kronqvist, N.,Westermark, P.,Jornvall, H.,Knight, S.,Ridderstrale, Y.,Holm, L.,Meng, Q.,Jaudzems, K.,Chesler, M.,Johansson, J.,Rising, A.
Carbonic Anhydrase Generates CO2 and H+ That Drive Spider Silk Formation Via Opposite Effects on the Terminal Domains
Plos Biol., 12:e1001921-e1001921, 2014

PubMed Abstract: Spider silk fibers are produced from soluble proteins (spidroins) under ambient conditions in a complex but poorly understood process. Spidroins are highly repetitive in sequence but capped by nonrepetitive N- and C-terminal domains (NT and CT) that are suggested to regulate fiber conversion in similar manners. By using ion selective microelectrodes we found that the pH gradient in the silk gland is much broader than previously known. Surprisingly, the terminal domains respond in opposite ways when pH is decreased from 7 to 5: Urea denaturation and temperature stability assays show that NT dimers get significantly stabilized and then lock the spidroins into multimers, whereas CT on the other hand is destabilized and unfolds into ThT-positive β-sheet amyloid fibrils, which can trigger fiber formation. There is a high carbon dioxide pressure (pCO2) in distal parts of the gland, and a CO2 analogue interacts with buried regions in CT as determined by nuclear magnetic resonance (NMR) spectroscopy. Activity staining of histological sections and inhibition experiments reveal that the pH gradient is created by carbonic anhydrase. Carbonic anhydrase activity emerges in the same region of the gland as the opposite effects on NT and CT stability occur. These synchronous events suggest a novel CO2 and proton-dependent lock and trigger mechanism of spider silk formation.

PubMed: 25093327
DOI: 10.1371/journal.pbio.1001921

実験手法

SOLUTION NMR