1B1E

CRYSTAL STRUCTURE OF HUMAN ANGIOGENIN VARIANT K40Q

1B1E の概要

• エントリーDOI: 10.2210/pdb1b1e/pdb
• 分子名称: HYDROLASE ANGIOGENIN, CITRIC ACID (3 entities in total)
• 機能のキーワード: hydrolase (vascurisation), hydrolase
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Cytoplasmic vesicle, secretory vesicle lumen : P03950
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 14360.11

構造登録者

Leonidas, D.D.,Acharya, K.R. (登録日: 1998-11-20, 公開日: 1999-04-02, 最終更新日: 2024-10-30)

主引用文献

Leonidas, D.D.,Shapiro, R.,Allen, S.C.,Subbarao, G.V.,Veluraja, K.,Acharya, K.R.
Refined crystal structures of native human angiogenin and two active site variants: implications for the unique functional properties of an enzyme involved in neovascularisation during tumour growth.
J.Mol.Biol., 285:1209-1233, 1999

PubMed Abstract: Human angiogenin (Ang), an unusual member of the pancreatic RNase superfamily, is a potent inducer of angiogenesis in vivo. Its ribonucleolytic activity is weak (10(4) to 10(6)-fold lower than that of bovine RNase A), but nonetheless seems to be essential for biological function. Ang has been implicated in the establishment of a wide range of human tumours and has therefore emerged as an important target for the design of new anti-cancer compounds. We report high-resolution crystal structures for native Ang in two different forms (Pyr1 at 1.8 A and Met-1 at 2.0 A resolution) and for two active-site variants, K40Q and H13A, at 2.0 A resolution. The native structures, together with earlier mutational and biochemical data, provide a basis for understanding the unique functional properties of this molecule. The major structural features that underlie the weakness of angiogenin's RNase activity include: (i) the obstruction of the pyrimidine-binding site by Gln117; (ii) the existence of a hydrogen bond between Thr44 and Thr80 that further suppresses the effectiveness of the pyrimidine site; (iii) the absence of a counterpart for the His119-Asp121 hydrogen bond that potentiates catalysis in RNase A (the corresponding aspartate in Ang, Asp116, has been recruited to stabilise the blockage of the pyrimidine site); and (iv) the absence of any precise structural counterparts for two important purine-binding residues of RNase A. Analysis of the native structures has revealed details of the cell-binding region and nuclear localisation signal of Ang that are critical for angiogenicity. The cell-binding site differs dramatically from the corresponding regions of RNase A and two other homologues, eosinophil-derived neurotoxin and onconase, all of which lack angiogenic activity. Determination of the structures of the catalytically inactive variants K40Q and H13A has now allowed a rigorous assessment of the relationship between the ribonucleolytic and biological activities of Ang. No significant change outside the enzymatic active site was observed in K40Q, establishing that the loss of angiogenic activity for this derivative is directly attributable to disruption of the catalytic apparatus. The H13A structure shows some changes beyond the ribonucleolytic site, but sites involved in cell-binding and nuclear translocation are essentially unaffected by the amino acid replacement.

PubMed: 9918722
DOI: 10.1006/jmbi.1998.2378

実験手法

X-RAY DIFFRACTION (2 Å)