(Salicylato)[tris­(1-methyl-1H-benz­imidazol-2-ylmeth­yl)amine]copper(II) perchlorate dimethyl­formamide disolvate

In the title complex, [Cu(C7H5O3)(C27H27N7)]ClO4·2C3H7NO, the CuII ion is five-coordinated by four N atoms from the tris­(1-methyl-1H-benzimidazol-2-ylmeth­yl)amine ligand and an O atom of the monodentate salicylate ligand. The N4O donor set defines a coordination geometry inter­mediate between square-pyramidal and trigonal–bipyramidal. The crystal structure is stabilized by O—H⋯O inter­actions. The atoms of the aromatic ring of the salicylate ligand are disordered over two sites of equal occupancy. In addition, one of the dimethyl­formamide solvent mol­ecules is partially disordered over two positions, of approximately equal occupancy

Bis[1,3-bis­(1-benzyl-1H-benzimidazol-2-yl)-2-oxapropane]zinc(II) dipicrate dimethyl­formamide disolvate

In the title compound, [Zn(C30H26N4O)2](C6H2N3O7)2·2C3H7NO, the ZnII ion is coordinated in a distorted octa­hedral environment involving four equatorial N atoms and two O atoms in axial sites. The dihedral angles between the benzimidazole ring system and the phenyl rings in each of the benzyl­benzimidazole units are 78.56 (12), 81.68 (11), 75.76 (10) and 85.78 (9)°. In the crystal structure, there are weak but significant inter­molecular π–π stacking inter­actions with centroid–centroid distances of 3.685 (1) and 3.978 (1) Å

Bis[bis­(1-ethyl­benzimidazol-2-ylmeth­yl) ether]cobalt(II) dipicrate dimethyl­formamide disolvate

In the title complex, [Co(C20H22N4O)2](C6H2N3O7)2·2C3H7NO, the CoII ion is coordinated by two sets of two N atoms and an O atom from two independent tridendate ligands in a distorted octa­hedral coordination environment. There are significant differences between chemically equivalent coordination bond lengths. The crystal structure is stabilized by weak inter­molecular C—H⋯O hydrogen bonds and weak π–π stacking inter­actions [centroid–centroid distance 3.495 (1) Å]. In one of the anions one nitro group is rotationally disordered about the C—N bond with refined occupancies of 0.524 (8) and 0.476 (8)

Bis[1,3-bis­(1-benzyl-1H-benzimidazol-2-yl)-2-oxapropane]nickel(II) dipicrate–dimethyl­formamide–ethanol (1/2/0.25)

In the title compound, [Ni(C30H26N4O)2](C6H2N3O7)2·2C3H7NO·0.25CH3CH2OH, the NiII ion is coordinated in a distorted octa­hedral environment by four N atoms and two O atoms from two tridendate 1,3-bis­(1-benzyl-1H-benzimidazol-2-yl)-2-oxapropane ligands. The crystal structure is stabilized by weak inter­molecular C—H⋯O hydrogen bonds and weak π–π stacking inter­actions [centroid–centroid distance 3.501 (3) Å]. As well as the cation, two anions and two dimethyl­formamide solvent mol­ecules, the asymmetric unit also contains an ethanol solvent molecule with 0.25 occupancy

Acrylato[tris­(1-methyl­benzimidazol-2-ylmeth­yl)amine]zinc(II) perchlorate–dimethyl­formamide–methanol (1/1/1.5) at 153 (2) K

In the title complex, [Zn(C3H3O2)(C27H27N7)](ClO4)·C3H7NO·1.5CH4O, the ZnII ion is five-coordinated by four N atoms from a tris­(1-methyl­benzimidazol-2-ylmeth­yl)amine (Mentb) ligand and one O atom from an acrylate ligand in a distorted trigonal–bipyramidal geometry with approximate mol­ecular C 3 symmetry. The atoms of the acrylate ligand are disordered over two sites, with approximate occupancies of 0.84 and 0.16. In addition, a methanol solvent mol­ecule is disordered over two sites with equal occupancies. In the crystal structure, the full-occupancy methanol is linked to a dimethyl­formamide mol­ecule by an inter­molecular O—H⋯O hydrogen bond

2,6-Bis(1H-benzimidazol­-2-yl)pyridine methanol trisolvate

In the title compound, C19H13N5·3CH4O, the 2,6-bis­(2-benzimidazol­yl)pyridine mol­ecule is essentially planar with an r.m.s. deviation for all non-H atoms of 0.185 Å. The crystal structure is stabilized by inter­molecular O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds and weak π⋯π stacking inter­actions with centroid–centroid distances of 3.6675 (16) and 3.6891 (15) Å. The atoms of one of the methanol solvent molecules are disordered over two sites with refined occupancies of 0.606(8) and 0.394(8)

1,3-Bis(1-benzyl-1H-benzimidazol-2-yl)-2-oxapropane

In the title compound, C30H26N4O, the dihedral angle between the two benzimidazole rings is 69.35 (9)°. The dihedral angles between the benzimidazole ring system and the phenyl ring are 76.79 (12) and 86.10 (11)° in the two benzyl­benzimidazole moieties

Transcriptional Repressor NIR Functions in the Ribosome RNA Processing of Both 40S and 60S Subunits

BACKGROUND: NIR was identified as an inhibitor of histone acetyltransferase and it represses transcriptional activation of p53. NIR is predominantly localized in the nucleolus and known as Noc2p, which is involved in the maturation of the 60S ribosomal subunit. However, how NIR functions in the nucleolus remains undetermined. In the nucleolus, a 47S ribosomal RNA precursor (pre-rRNA) is transcribed and processed to produce 18S, 5.8S and 28S rRNAs. The 18S rRNA is incorporated into the 40S ribosomal subunit, whereas the 28S and 5.8S rRNAs are incorporated into the 60S subunit. U3 small nucleolar RNA (snoRNA) directs 18S rRNA processing and U8 snoRNA mediates processing of 28S and 5.8 S rRNAs. Functional disruption of nucleolus often causes p53 activation to inhibit cell proliferation. METHODOLOGY/PRINCIPAL FINDINGS: Western blotting showed that NIR is ubiquitously expressed in different human cell lines. Knock-down of NIR by siRNA led to inhibition of the 18S, 28S and 5.8S rRNAs evaluated by pulse-chase experiment. Pre-rRNA particles (pre-rRNPs) were fractionated from the nucleus by sucrose gradient centrifugation and analysis of the pre-RNPs components showed that NIR existed in the pre-RNPs of both the 60S and 40S subunits and co-fractionated with 32S and 12S pre-rRNAs in the 60S pre-rRNP. Protein-RNA binding experiments demonstrated that NIR is associated with the 32S pre-rRNA and U8 snoRNA. In addition, NIR bound U3 snoRNA. It is a novel finding that depletion of NIR did not affect p53 protein level but de-repressed acetylation of p53 and activated p21. CONCLUSIONS: We provide the first evidence for a transcriptional repressor to function in the rRNA biogenesis of both the 40S and 60S subunits. Our findings also suggested that a nucleolar protein may alternatively signal to p53 by affecting the p53 modification rather than affecting p53 protein level