8RSA

CRYSTAL STRUCTURE OF TWO COVALENT NUCLEOSIDE DERIVATIVES OF RIBONUCLEASE A

8RSA の概要

• エントリーDOI: 10.2210/pdb8rsa/pdb
• 分子名称: RIBONUCLEASE A, 3'-DEOXY-3'-ACETAMIDO-THYMIDINE (3 entities in total)
• 機能のキーワード: hydrolase (phosphoric diester)
• 由来する生物種: Bos taurus (cattle)
• 細胞内の位置: Secreted: P61823
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 27983.21

構造登録者

Nachman, J.,Wlodawer, A. (登録日: 1989-08-28, 公開日: 1991-04-15, 最終更新日: 2024-11-06)

主引用文献

Nachman, J.,Miller, M.,Gilliland, G.L.,Carty, R.,Pincus, M.,Wlodawer, A.
Crystal structure of two covalent nucleoside derivatives of ribonuclease A.
Biochemistry, 29:928-937, 1990

PubMed Abstract: Crystal structures of two forms of ribonuclease A with deoxynucleosides covalently bound to respectively His 12 and His 119 have been solved. One form, T-H12-RNase, has a deoxythymidine bound to N epsilon 2 of His 12, while the other one, U-H119-RNase, has a deoxyuridine bound to N delta 1 of His 119. The two crystal forms are nearly isomorphous, with two molecules in the asymmetric unit. However, the modified ribonucleases differ both in their enzymatic activities and in the conformation of the catalytic site and of the deoxynucleoside-histidine moiety. T-H12-RNase is characterized by complete loss of enzymatic activity; in this form the deoxynucleoside completely blocks the catalytic site and forms intramolecular contacts with residues associated with both the B1 and B2 sites. U-H119-RNase retains 1% of the activity of the unmodified enzyme, and in this form His 119 adopts a different orientation, corresponding to the alternate conformation reported for this residue; the deoxynucleoside-histidine moiety points out of the active site and does not form any contacts with the rest of the protein, thus allowing partial access to the catalytic site. On the basis of these structures, we propose possible mechanisms for the reactions of bromoacetamido nucleosides with ribonuclease A.

PubMed: 2340284
DOI: 10.1021/bi00456a012

実験手法

X-RAY DIFFRACTION (1.8 Å)