8WP9

Small-heat shock protein from Methanocaldococcus jannaschii, Hsp16.5

8WP9 の概要

• エントリーDOI: 10.2210/pdb8wp9/pdb
• 関連するPDBエントリー: 1SHS
• EMDBエントリー: 37712 37713
• 分子名称: Small heat shock protein HSP16.5 (1 entity in total)
• 機能のキーワード: hsp16.5; molecular chaperone; oligomeric protein; small heat-shock protein; stress response, chaperone
• 由来する生物種: Methanocaldococcus jannaschii DSM 2661
• タンパク質・核酸の鎖数: 24
• 化学式量合計: 395279.76

構造登録者

Lee, J.,Ryu, B.,Kim, T.,Kim, K.K. (登録日: 2023-10-09, 公開日: 2023-12-27)

主引用文献

Lee, J.,Ryu, B.,Kim, T.,Kim, K.K.
Cryo-EM structure of a 16.5-kDa small heat-shock protein from Methanocaldococcus jannaschii.
Int.J.Biol.Macromol., 258:128763-128774, 2024

PubMed Abstract: The small heat-shock protein (sHSP) from the archaea Methanocaldococcus jannaschii, MjsHSP16.5, functions as a broad substrate ATP-independent holding chaperone protecting misfolded proteins from aggregation under stress conditions. This protein is the first sHSP characterized by X-ray crystallography, thereby contributing significantly to our understanding of sHSPs. However, despite numerous studies assessing its functions and structures, the precise arrangement of the N-terminal domains (NTDs) within this sHSP cage remains elusive. Here we present the cryo-electron microscopy (cryo-EM) structure of MjsHSP16.5 at 2.49-Å resolution. The subunits of MjsHSP16.5 in the cryo-EM structure exhibit lesser compaction compared to their counterparts in the crystal structure. This structural feature holds particular significance in relation to the biophysical properties of MjsHSP16.5, suggesting a close resemblance to this sHSP native state. Additionally, our cryo-EM structure unveils the density of residues 24-33 within the NTD of MjsHSP16.5, a feature that typically remains invisible in the majority of its crystal structures. Notably, these residues show a propensity to adopt a β-strand conformation and engage in antiparallel interactions with strand β1, both intra- and inter-subunit modes. These structural insights are corroborated by structural predictions, disulfide bond cross-linking studies of Cys-substitution mutants, and protein disaggregation assays. A comprehensive understanding of the structural features of MjsHSP16.5 expectedly holds the potential to inspire a wide range of interdisciplinary applications, owing to the renowned versatility of this sHSP as a nanoscale protein platform.

PubMed: 38103675
DOI: 10.1016/j.ijbiomac.2023.128763

実験手法

ELECTRON MICROSCOPY (2.49 Å)