6FLO

Regulatory subunit of a cAMP-independent protein kinase A from Trypanosoma brucei at 2.1 Angstrom resolution

6FLO の概要

• エントリーDOI: 10.2210/pdb6flo/pdb
• 関連するPDBエントリー: 1RGS 6FTF
• 分子名称: Protein kinase A regulatory subunit, INOSINE, GLYCEROL, ... (4 entities in total)
• 機能のキーワード: protein kinase a, regulatory subunit, nucleoside-binding protein, signaling protein
• 由来する生物種: Trypanosoma brucei brucei TREU927
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 70083.15

構造登録者

Volpato Santos, Y.,Lorentzen, E.,Basquin, J.,Boshart, M. (登録日: 2018-01-26, 公開日: 2019-08-14, 最終更新日: 2024-04-10)

主引用文献

Ober, V.T.,Githure, G.B.,Volpato Santos, Y.,Becker, S.,Moya Munoz, G.,Basquin, J.,Schwede, F.,Lorentzen, E.,Boshart, M.
Purine nucleosides replace cAMP in allosteric regulation of PKA in trypanosomatid pathogens.
Elife, 12:-, 2024

PubMed Abstract: Cyclic nucleotide binding domains (CNB) confer allosteric regulation by cAMP or cGMP to many signaling proteins, including PKA and PKG. PKA of phylogenetically distant is the first exception as it is cyclic nucleotide-independent and responsive to nucleoside analogues (Bachmaier et al., 2019). Here, we show that natural nucleosides inosine, guanosine and adenosine are nanomolar affinity CNB ligands and activators of PKA orthologs of the important tropical pathogens , and . The sequence and structural determinants of binding affinity, -specificity and kinase activation of PKAR were established by structure-activity relationship (SAR) analysis, co-crystal structures and mutagenesis. Substitution of two to three amino acids in the binding sites is sufficient for conversion of CNB domains from nucleoside to cyclic nucleotide specificity. In addition, a trypanosomatid-specific C-terminal helix (αD) is required for high affinity binding to CNB-B. The αD helix functions as a lid of the binding site that shields ligands from solvent. Selectivity of guanosine for CNB-B and of adenosine for CNB-A results in synergistic kinase activation at low nanomolar concentration. PKA pulldown from rapid lysis establishes guanosine as the predominant ligand in vivo in bloodstream forms, whereas guanosine and adenosine seem to synergize in the procyclic developmental stage in the insect vector. We discuss the versatile use of CNB domains in evolution and recruitment of PKA for novel nucleoside-mediated signaling.

PubMed: 38517938
DOI: 10.7554/eLife.91040

実験手法

X-RAY DIFFRACTION (2.138686637 Å)