1XKI

Crystal structure of human tear lipocalin/von Ebners gland protein

1XKI の概要

• エントリーDOI: 10.2210/pdb1xki/pdb
• 分子名称: Von Ebner's gland protein, ZINC ION, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: beta barrel, ligand binding protein, transport protein
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Secreted: P31025
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 18216.31

構造登録者

Breustedt, D.A.,Korndoerfer, I.P.,Redl, B.,Skerra, A. (登録日: 2004-09-29, 公開日: 2004-10-19, 最終更新日: 2024-05-29)

主引用文献

Breustedt, D.A.,Korndoerfer, I.P.,Redl, B.,Skerra, A.
The 1.8-A crystal structure of human tear lipocalin reveals an extended branched cavity with capacity for multiple ligands
J.Biol.Chem., 280:484-493, 2005

PubMed Abstract: In contrast with earlier assumptions, which classified human tear lipocalin (Tlc) as an outlier member of the lipocalin protein family, the 1.8-A resolution crystal structure of the recombinant apoprotein confirms the typical eight-stranded antiparallel beta-barrel architecture with an alpha-helix attached to it. The fold of Tlc most closely resembles the bovine dander allergen Bos d 2, a well characterized prototypic lipocalin, but also reveals similarity with beta-lactoglobulin. However, compared with other lipocalin structures Tlc exhibits an extremely wide ligand pocket, whose entrance is formed by four partially disordered loops. The cavity deeply extends into the beta-barrel structure, where it ends in two distinct lobes. This unusual structural feature explains the known promiscuity of Tlc for various ligands, with chemical structures ranging from lipids and retinoids to the macrocyclic antibiotic rifampin and even to microbial siderophores. Notably, earlier findings of biological activity as a thiol protease inhibitor have no correspondence in the three-dimensional structure of Tlc, rather it appears that its proteolytic fragments could be responsible for this phenomenon. Hence, the present structural analysis sheds new light on the ligand binding activity of this functionally obscure but abundant human lipocalin.

PubMed: 15489503
DOI: 10.1074/jbc.M410466200

実験手法

X-RAY DIFFRACTION (1.8 Å)