5HCI

GPN-loop GTPase Npa3 in complex with GDP

5HCI の概要

• エントリーDOI: 10.2210/pdb5hci/pdb
• 分子名称: GPN-loop GTPase 1, GUANOSINE-5'-DIPHOSPHATE, MAGNESIUM ION, ... (5 entities in total)
• 機能のキーワード: gpn-loop gtpase, chaperone, assembly, rna polymerase, hydrolase
• 由来する生物種: Saccharomyces cerevisiae (Baker's yeast)
• 細胞内の位置: Cytoplasm : P47122
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 180676.34

構造登録者

Niesser, J.,Wagner, F.R.,Kostrewa, D.,Muehlbacher, W.,Cramer, P. (登録日: 2016-01-04, 公開日: 2016-01-20, 最終更新日: 2024-05-08)

主引用文献

Niesser, J.,Wagner, F.R.,Kostrewa, D.,Muhlbacher, W.,Cramer, P.
Structure of GPN-Loop GTPase Npa3 and Implications for RNA Polymerase II Assembly.
Mol.Cell.Biol., 36:820-831, 2015

PubMed Abstract: Biogenesis of the 12-subunit RNA polymerase II (Pol II) transcription complex requires so-called GPN-loop GTPases, but the function of these enzymes is unknown. Here we report the first crystal structure of a eukaryotic GPN-loop GTPase, the Saccharomyces cerevisiae enzyme Npa3 (a homolog of human GPN1, also called RPAP4, XAB1, and MBDin), and analyze its catalytic mechanism. The enzyme was trapped in a GDP-bound closed conformation and in a novel GTP analog-bound open conformation displaying a conserved hydrophobic pocket distant from the active site. We show that Npa3 has chaperone activity and interacts with hydrophobic peptide regions of Pol II subunits that form interfaces in the assembled Pol II complex. Biochemical results are consistent with a model that the hydrophobic pocket binds peptides and that this can allosterically stimulate GTPase activity and subsequent peptide release. These results suggest that GPN-loop GTPases are assembly chaperones for Pol II and other protein complexes.

PubMed: 26711263
DOI: 10.1128/MCB.01009-15

実験手法

X-RAY DIFFRACTION (2.3 Å)