PDBsum entry 6e2b

Protein binding

PDB id: 6e2b

Contents

Protein chains

(+ 0 more) 76 a.a.

Ligands

SO4 ×6

GOL ×8

PT7 ×3

Waters ×585

PDB id:

6e2b

Name:

Protein binding

Title:

Ubiquitin in complex with pt(2-phenilpyridine)(pph3)

Structure:

Ubiquitin. Chain: a, c, e, g, i, p

Source:

Bos taurus. Bovine. Organism_taxid: 9913. Cell: erythrocytes

Resolution:

1.45Å R-factor: 0.182 R-free: 0.207

Authors:

V.A.Zhemkov,M.Kim

Key ref:

A.I.Solomatina et al. (2019). Reactions of Cyclometalated Platinum(II) [Pt(N^∧C)(PR₃)Cl] Complexes with Imidazole and Imidazole-Containing Biomolecules: Fine-Tuning of Reactivity and Photophysical Properties via Ligand Design. Inorg Chem, 58, 204-217. PubMed id: 30376305 DOI: 10.1021/acs.inorgchem.8b02204

Date:

11-Jul-18 Release date: 14-Nov-18

Protein chains

P62992  (RS27A_BOVIN) -  Ubiquitin-ribosomal protein eS31 fusion protein from Bos taurus

Seq: 156 a.a.

Struc: 76 a.a.

DOI no: 10.1021/acs.inorgchem.8b02204

Inorg Chem 58:204-217 (2019)

PubMed id: 30376305

Reactions of Cyclometalated Platinum(II) [Pt(N^∧C)(PR₃)Cl] Complexes with Imidazole and Imidazole-Containing Biomolecules: Fine-Tuning of Reactivity and Photophysical Properties via Ligand Design.

A.I.Solomatina, P.S.Chelushkin, T.O.Abakumova, V.A.Zhemkov, M.Kim, I.Bezprozvanny, V.V.Gurzhiy, A.S.Melnikov, Y.A.Anufrikov, I.O.Koshevoy, S.H.Su, P.T.Chou, S.P.Tunik.

ABSTRACT

This work describes interaction of a family of [Pt(N^∧C)(PR₃)Cl] complexes with imidazole (Im), possible application of this chemistry for regioselective labeling of proteins through imidazole rings of histidine residues and employment of the resulting phosphorescent products in bioimaging. It was found that the complexes containing aliphatic phosphines display reversible substitution of chloride ligand for imidazole function that required considerable excess of imidazole to obtain full conversion into the substituted [Pt(ppy)(PR₃)(Im)] product, whereas the substitution in the complexes with aromatic phosphines readily proceeds in 1:1.5 mixture of reagents. Rapid, selective, and quantitative coordination of imidazole to the platinum complexes enabled regioselective labeling of ubiquitin. X-ray protein crystallography of the {[Pt(ppy)(PPh₃)]/ubiquitin} conjugate revealed direct bonding of the platinum center to unique histidine-68 residue through the nitrogen atom of imidazole function, the coordination being also supported by noncovalent interaction of the ligands with the protein secondary structure. The variations of the cyclometalating N^∧C ligands gave a series of [Pt(N^∧C)(PPh₃)Cl] complexes (N^∧C = 2-phenylpyridine, 2-(benzofuran-3-yl)pyridine, 2-(benzo[b]thiophen-3-yl)pyridine, methyl-2-phenylquinoline-4-carboxylate), which were used to investigate the impact of N^∧C-ligand onto photophysical properties of the imidazole complexes and conjugates with human serum albumin (HSA). The chloride ligand substitution for imidazole and formation of the conjugates results in ignition of the platinum chromophore luminescence with substantially higher quantum yield in the latter case. Variation of the metalating N^∧C-ligand made possible the shift of the emission to the red region of visible spectrum for both types of the products. Cell-viability tests revealed low cytotoxicity of all {[Pt(N^∧C)(PPh₃)Cl]/HSA} conjugates, while PLIM experiments demonstrated their high potential for oxygen sensing.