Elucidation of the binding sites of two novel Ru(II) complexes on bovine serum albumin.

Hyphenated mass spectrometry (MS) techniques have attained an important position in analysis of covalent and non-covalent interactions of metal complexes with peptides and proteins. The aim of the present study was to qualitatively and quantitatively determine ruthenium binding sites on a protein using tandem mass spectrometry and allied techniques, i.e. liquid chromatography (LC) and inductively coupled plasma optical emission spectrometry (ICP-OES). For that purpose, two newly synthesized Ru(II) complexes of a meridional geometry, namely mer-[Ru(4' Cl-tpy)(en)Cl](+) (1) and mer-[Ru(4' Cl-tpy)(dach)Cl](+) (2) (where 4' Cl-tpy=4'-chloro-2,2':6',2″-terpyridine, en=1,2-diaminoethane and dach=1,2-diaminocyclohexane), and bovine serum albumin were used. The binding of the complexes to the protein was investigated by means of size exclusion- and reversed phase-LC, ICP OES, matrix-assisted laser desorption ionization MS and MS/MS. Ruthenated peptide sequence and a binding target amino acid were revealed through accurate elucidation of MS/MS spectra. The results obtained in this study suggest a high binding capacity of the protein towards both complexes, with up to 5.77±0.14 and 6.95±0.43mol of 1 and 2 bound per mol of protein, respectively. The proposed binding mechanism for the selected complexes includes the release of Cl ligand, its replacement with water molecule and further coordination to electron donor histidine residue.

Histological groups of human postpubertal testicular germ cell tumours harbour different genetic alterations.

BACKGROUND: Testicular germ cell tumours are the most common malignancies in young males. Molecular biology studies of these tumours are often contradictory. Two histological groups, seminoma and non-seminoma, differ both morphologically and in malignant behaviour. Although a common cytogenetic feature is seen, namely the amplification of the 12p chromosomal region, the development mechanisms of less aggressive seminomas and more aggressive non-seminomas are unknown. MATERIALS AND METHODS: Occurrence of structural genetic alterations was analyzed in 18 seminomas and 22 non-seminomas for genes involved in the malignant tumour phenotype: cadherin 1, Type 1, E-cadherin (Epithelial), CDH1; adenomatous polyposis coli, APC; NME/NM23 nucleoside diphosphate kinase 1, NME1; tumour protein P53, TP53; cyclin-dependent kinase inhibitor 2A, CDKN2A; retinoblastoma 1, RB1; RAD51 recombinase, RAD51; mutS homolog 2, MSH2; MutL homolog 1, MLH1; breast cancer 1, early onset, BRCA1; BCL2-Associated X Protein, BAX; ATP-Binding Cassette, Sub-Family G (WHITE), Member 2, ABCG2. Genetic alterations, loss of heterozygosity and microsatellite instability, were analyzed using restriction fragment or microsatellite repeat length polymorphisms. RESULTS: A difference in genetic alteration occurrence between seminomas and non-seminomas was observed. CONCLUSION: Occurrence of genetic alterations correlates with clinical behaviour of these tumours and may indicate that such alterations could occur early in the development of seminomas and non-seminomas.