5W4E

Importin binding to Tdt NLS peptide

5W4E の概要

• エントリーDOI: 10.2210/pdb5w4e/pdb
• 関連するPDBエントリー: 5W4F 5W4G
• 分子名称: Importin subunit alpha-1,Importin subunit alpha-1, human DNA repair polymerase Tdt, GLYCEROL, ... (4 entities in total)
• 機能のキーワード: importin, nls, tdt, nuclear transport, protein binding
• 由来する生物種: Glaciozyma antarctica; 詳細
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 59283.18

構造登録者

Pedersen, L.C.,London, R. (登録日: 2017-06-10, 公開日: 2018-06-27, 最終更新日: 2023-10-04)

主引用文献

Kirby, T.W.,Pedersen, L.C.,Gabel, S.A.,Gassman, N.R.,London, R.E.
Variations in nuclear localization strategies among pol X family enzymes.
Traffic, 2018

PubMed Abstract: Despite the essential roles of pol X family enzymes in DNA repair, information about the structural basis of their nuclear import is limited. Recent studies revealed the unexpected presence of a functional nuclear localization signal (NLS) in DNA polymerase β, indicating the importance of active nuclear targeting, even for enzymes likely to leak into and out of the nucleus. The current studies further explore the active nuclear transport of these enzymes by identifying and structurally characterizing the functional NLS sequences in the three remaining human pol X enzymes: terminal deoxynucleotidyl transferase (TdT), DNA polymerase mu (pol μ) and DNA polymerase lambda (pol λ). NLS identifications are based on Importin α (Impα) binding affinity determined by fluorescence polarization of fluorescein-labeled NLS peptides, X-ray crystallographic analysis of the Impα∆IBB•NLS complexes and fluorescence-based subcellular localization studies. All three polymerases use NLS sequences located near their N-terminus; TdT and pol μ utilize monopartite NLS sequences, while pol λ utilizes a bipartite sequence, unique among the pol X family members. The pol μ NLS has relatively weak measured affinity for Impα, due in part to its proximity to the N-terminus that limits non-specific interactions of flanking residues preceding the NLS. However, this effect is partially mitigated by an N-terminal sequence unsupportive of Met1 removal by methionine aminopeptidase, leading to a 3-fold increase in affinity when the N-terminal methionine is present. Nuclear targeting is unique to each pol X family enzyme with variations dependent on the structure and unique functional role of each polymerase.

PubMed: 29931796
DOI: 10.1111/tra.12600

実験手法

X-RAY DIFFRACTION (2.18 Å)