2XGX

Crystal structure of transcription factor NtcA from Synechococcus elongatus (mercury derivative)

2XGX の概要

• エントリーDOI: 10.2210/pdb2xgx/pdb
• 関連するPDBエントリー: 2XHK 2XKO 2XKP
• 分子名称: GLOBAL NITROGEN REGULATOR, 2-OXOGLUTARIC ACID, MERCURY (II) ION, ... (5 entities in total)
• 機能のキーワード: nitrogen assimilation, transcription, crp/fnr superfamily, cyanobacteria, 2-oxoglutarate
• 由来する生物種: SYNECHOCOCCUS ELONGATUS
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 50626.72

構造登録者

Llacer, J.L.,Castells, M.A.,Rubio, V. (登録日: 2010-06-08, 公開日: 2010-08-18, 最終更新日: 2024-05-08)

主引用文献

Llacer, J.L.,Espinosa, J.,Castells, M.A.,Contreras, A.,Forchhammer, K.,Rubio, V.
Structural Basis for the Regulation of Ntca-Dependent Transcription by Proteins Pipx and Pii.
Proc.Natl.Acad.Sci.USA, 107:15397-, 2010

PubMed Abstract: PII, an ancient and widespread signaling protein, transduces nitrogen/carbon/energy abundance signals through interactions with target proteins. We clarify structurally how PII regulates gene expression mediated by the transcription factor NtcA, the global nitrogen regulator of cyanobacteria, shedding light on NtcA structure and function and on how NtcA is activated by 2-oxoglutarate (2OG) and coactivated by the nonenzymatic PII target, protein PipX. We determine for the cyanobacteria Synechococcus elongatus the crystal structures of the PII-PipX and PipX-NtcA complexes and of NtcA in active and inactive conformations (respective resolutions, 3.2, 2.25, 2.3, and 3.05 A). The structures and the conclusions derived from them are consistent with the results of present and prior site-directed mutagenesis and functional studies. A tudor-like domain (TLD) makes up most of the PipX structure and mediates virtually all the contacts of PipX with PII and NtcA. In the PII-PipX complex, one PII trimer sequesters the TLDs of three PipX molecules between its body and its extended T loops, preventing PipX activation of NtcA. Changes in T loop conformation triggered by 2OG explain PII-PipX dissociation when 2OG is bound. The structure of active dimeric NtcA closely resembles that of the active cAMP receptor protein (CRP). This strongly suggests that with these proteins DNA binding, transcription activation, and allosteric regulation occur by common mechanisms, although the effectors are different. The PipX-NtcA complex consists of one active NtcA dimer and two PipX monomers. PipX coactivates NtcA by stabilizing its active conformation and by possibly helping recruit RNA polymerase but not by providing extra DNA contacts.

PubMed: 20716687
DOI: 10.1073/PNAS.1007015107

実験手法

X-RAY DIFFRACTION (2.85 Å)