Insights into the binding sites of organometallic ruthenium anticancer compounds on peptides using ultra-high resolution mass spectrometry.
The binding sites of two ruthenium(II) organometallic complexes of the form [(η(6)-arene)Ru(N,N)Cl](+), where arene/N,N = biphenyl (bip)/bipyridine (bipy) for complex AH076, and biphenyl (bip)/o-phenylenediamine (o-pda) for complex AH078, on the peptides angiotensin and bombesin have been investigated using Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Fragmentation was performed using collisionally activated dissociation (CAD), with, in some cases, additional data being provided by electron capture dissociation (ECD). The primary binding sites were identified as methionine and histidine, with further coordination to phenylalanine, potentially through a π-stacking interaction, which has been observed here for the first time. This initial peptide study was expanded to investigate protein binding through reaction with insulin, on which the binding sites proposed are histidine, glutamic acid, and tyrosine. Further reaction of the ruthenium complexes with the oxidized B chain of insulin, in which two cysteine residues are oxidized to cysteine sulfonic acid (Cys-SO3H), and glutathione, which had been oxidized with hydrogen peroxide to convert the cysteine to cysteine sulfonic acid, provided further support for histidine and glutamic acid binding, respectively.
Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
Rebecca H
RH
Wills
Abraha
A
Habtemariam
Andrea F
AF
Lopez-Clavijo
Mark P
MP
Barrow
Peter J
PJ
Sadler
Peter B
PB
O'Connor
D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D013058:Mass Spectrometry / Q000379:methods*; D008969:Molecular Sequence Data; D009942:Organometallic Compounds / Q000737:chemistry* / Q000378:metabolism; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017975:Ruthenium Compounds / Q000737:chemistry* / Q000378:metabolism
D000970:Antineoplastic Agents; D009942:Organometallic Compounds; D010455:Peptides; D017975:Ruthenium Compounds