3NOK

Crystal structure of Myxococcus xanthus Glutaminyl Cyclase

3NOK の概要

• エントリーDOI: 10.2210/pdb3nok/pdb
• 分子名称: Glutaminyl Cyclase, CALCIUM ION, 2-(N-MORPHOLINO)-ETHANESULFONIC ACID, ... (6 entities in total)
• 機能のキーワード: beta-propeller, glutaminyl cyclase, cyclotransferase, pyroglutamate, transferase
• 由来する生物種: Myxococcus xanthus
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 59785.50

構造登録者

Parthier, C.,Carrillo, D.R.,Stubbs, M.T. (登録日: 2010-06-25, 公開日: 2010-11-03, 最終更新日: 2024-11-20)

主引用文献

Carrillo, D.R.,Parthier, C.,Janckel, N.,Grandke, J.,Stelter, M.,Schilling, S.,Boehme, M.,Neumann, P.,Wolf, R.,Demuth, H.U.,Stubbs, M.T.,Rahfeld, J.U.
Kinetic and structural characterization of bacterial glutaminyl cyclases from Zymomonas mobilis and Myxococcus xanthus
Biol.Chem., 391:1419-1428, 2010

PubMed Abstract: Although enzymes responsible for the cyclization of amino-terminal glutamine residues are present in both plant and mammal species, none have yet been characterized in bacteria. Based on low sequence homologies to plant glutaminyl cyclases (QCs), we cloned the coding sequences of putative microbial QCs from Zymomonas mobilis (ZmQC) and Myxococcus xanthus (MxQC). The two recombinant enzymes exhibited distinct QC activity, with specificity constants k(cat)/K(m) of 1.47±0.33 mm⁻¹ s⁻¹ (ZmQC) and 142±32.7 mm⁻¹ s⁻¹ (MxQC) towards the fluorescent substrate glutamine-7-amino-4-methyl-coumarine. The measured pH-rate profile of the second order rate constant displayed an interesting deviation towards the acidic limb of the pH chart in the case of ZmQC, whereas MxQC showed maximum activity in the mild alkaline pH range. Analysis of the enzyme variants ZmQCGlu⁴⁶Gln and MxQCGln⁴⁶Glu show that the exchanged residues play a significant role in the pH behaviour of the respective enzymes. In addition, we determined the three dimensional crystal structures of both enzymes. The tertiary structure is defined by a five-bladed β-propeller anchored by a core cation. The structures corroborate the putative location of the active site and confirm the proposed relation between bacterial and plant glutaminyl cyclases.

PubMed: 20868223
DOI: 10.1515/BC.2010.130

実験手法

X-RAY DIFFRACTION (1.65 Å)