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Surface topography and texture of cell culture substrata can affect the differentiation and growth of adherent cells. The biochemical basis of the transduction of the physical and mechanical signals to cellular responses is not well understood. The lack of a systematic characterization of cell-biomaterial interaction is the major bottleneck. This study demonstrated the use of a novel subcellular fractionation method combined with quantitative MS-based proteomics to enable the robust and high-throughput analysis of proteins at the adherence interface of Madin-Darby canine kidney cells. This method revealed the enrichment of extracellular matrix proteins and membrane and stress fibers proteins at the adherence surface, whereas it shows depletion of extracellular matrix belonging to the cytoplasmic, nucleus, and lateral and apical membranes. The asymmetric distribution of proteins between apical and adherence sides was also profiled. Apart from classical proteins with clear involvement in cell-material interactions, proteins previously not known to be involved in cell attachment were also discovered. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc., link_to_OA_fulltext

Nitridoosmium(VI) complexes of substituted 2,2′-bipyridines and 1,10-phenanthrolines have been prepared from [OsNCl4]– and the appropriate chelating ligands in acetonitrile. Reaction of [Os(bipy)NCl3](bipy = 2,2′-bipyridine) and [Os(terpy)NCl2]Cl (terpy = 2,2′ : 6′,2″-terpyridine) with neat trifluoromethanesulfonic acid gave [Os(bipy)NCl2(H2O)]+ and [Os(terpy)N(Cl)(CF3SO3)]+ respectively. The crystal structures of [Os(dmbipy)NCl3](dmbipy = 5,5′-dimethyl-2,2′-bipyridine), [Os(bipy)NCl2(H2O)]+ and [Os(terpy)N(Cl)(CF3SO3)]+ show that the OsN distances are 1.68(1), 1.630(7) and 1.629(8)A respectively. In the latter two complexes the OsN moiety is perpendicular to the plane of the chelating ligand. The spectroscopic, photophysical and photochemical properties of the newly prepared complexes have been studied. All have long-lived and emissive 3[dxy′,dπ.] excited states in the solid state and in fluid solution at room temperature. The complex mer-[Os(terpy)NCl2][ClO4] has the longest emission lifetime 4.64 µs (at infinite dilution) in degassed acetonitrile at room temperature. Based on quenching studies with aromatic hydrocarbons, this complex is a powerful photooxidant with E⊖[OsVI*–OsV] being 2.12(30)V vs. the normal hydrogen electrode.

The d 10 -d 8 heterobimetallic complexes [AuPt(dppm) 2 (CN) 2 ]ClO 2 and [AgPt(dppm) 2 (CN) 2 (CF 3 SO 3 )] (dppm= bis(diphenylphosphino)methane) were prepared by literature methods. The X-ray crystal structure of [AgPt(dppm) 2 (CN) 2 (CF 3 SO 3 )] has been determined. Crystal data for [AgPt(dppm) 2 (CN) 2 (CF 3 SO 3 )]: monoclinic, space group P2 1 , a=10.453(2) A, b=16.372(4) A, c=14.846(6) A, and β=92.17(2) o

The reaction of [Au(C≡CPh]∞ with dppm [bis(diphenylphosphino)methane] in ethanol gave [Au3(μ2-dppm)2(C≡CPh)2][Au(C≡CPh)2]. The complex has been characterized by X-ray crystal analysis. The structure consists of a trinuclear. [Au3(μ2-dppm)2 (C≡CPh)2]+ cation with the three gold atoms arranged in an isosceles triangle. The intramolecular AuċAu separations are 3.083(2) and 3.167(2)A˚. At room temperature, the [Au3(μ2-dppm)2(C≡CPh)2][Au(C≡CPh)2] complex is photoluminescent in the solid state and in solution.

The spectroscopic and luminescent properties of the heterobimetallic [PtRh(dppm) 2 (CN) 2 (CN-t-Bu) 2 ]ClO 4 , [AuRh(dppm) 2 (CN-t-Bu) 2 ] (ClO 4 ) 2 , and [AgRh(dppm) 2 (CN-t-Bu) 2 ] (ClO 4 ) 2 complexes were investigated. All the three complexes display an intense 1 (dσ * →pσ) transition at 473 nm (e max =1.34×10 9 M.cm -1 ), 473 nm e max =2.40 ×10 4 s M -1 cm -1 ), and 425 nm (e max =1.68×10 4 M -1 cm -1 ), respectively

The complexes [Pt(terpy)L′]n+(terpy = 2,2′:6′,2″-terpyridine; L′= Cl, Br, I, N3 or SCN–, n= 1; L′= NH3, n= 2) have been prepared and their spectroscopic and emission properties studied. Absorption bands are found at 300–350 and at 370–450 nm, which are assigned to the intraligand and metal-to-ligand change-transfer (m.l.c.t.) transitions, respectively. The complexes [Pt(4′R-terpy)Cl]ClO4(R′= C6H4OMe-p,C6H4Me-p, C6H4Br-p or C6H4CN-p) were prepared by the reaction of K2[PtCl4] with 4′R-terpy in water–MeCN. Unlike [Pt(terpy)L′]n+ which show emission in the solid state only, [Pt(4′R-terpy)Cl]+ display 3m.l.c.t. emission in fluid solution at room temperature. The crystal structure of [Pt(terpy)Cl][CF3SO3] has been determined: monoclinic, space group P21/n, a= 13.808(4), b= 6.873(1), c= 19.477(5)A, β= 105.54(2)°, and Z= 4. In the unit cell, two [Pt(terpy)Cl]+ cations stack in a head-to-tail fashion with an intermolecular Pt ⋯ Pt distance of 3.329(1)A. The solid-state emission of [Pt(terpy)Cl][CF3SO3] is similar to that of the 3(dσ*πb) emission of the dinuclear complex [Pt2(terpy)2L][ClO4]3(L = guadinate) having intramolecular Pt ⋯ Pt separations of 3.090(1) and 3.071(1)A.

The crystal structure of [AuPt(dppm)2(CCPh)2]PF6·H2O (dppm = Ph2PCH2PPh2) has been determined: triclinic, space group P, Z= 2, a= 11.146(4), b= 14.512(2), c= 20.322(3)A, α= 81.55(1), β= 101.27(2), γ= 109.35(2)°. The complex cation consists of a square-planar P–Pt(CCPh)2–P and a linear P–Au–P moiety and the measured intramolecular Pt–Au separation is 2.910(1)A. The absorption and emission spectra of the complex and of [AgPt(dppm)2(CCPh)2]PF6 and trans-[Pt(dppm)2(CCPh)2] have been measured. Both dinuclear complexes possess low-energy intense electronic absorption bands {[AuPt(dppm)2(CCPh)2]PF6, λmax= 387 nm, Iµmax= 1.11 × 104 dm3 mol–1 cm–1; [AgPt(dppm)2(CCPh)2]PF6, λmax= 368, Iµmax= 1.63 × 104 dm3 mol–1 cm–1} which are red-shifted from that of trans-[Pt(dppm)2(CCPh)2]. In solid form, all three complexes exhibit photoluminescence at room temperature. Extended-Huckel molecular orbital calculations have been performed on the model complexes [AuPt(dmpm)2(CCPh)2]+ and trans-[Pt(dmpm)2(CCPh)2](dmpm = Me2PCH2PMe2).

The synthesis and X-ray crystal structures of [Au(tBuNC)(CN)], [Au2(dmb)(CN)2] (dmb = 1,8-diisocyano-p-menthane) and [Au2(tmb)(CN)2] (tmb=2,5-diisocyano-2,5-dimethylhexane) are described. [Au(tBuNC)(CN)]: space group Pnma, a=13.437(1), b=6.469(1), c=9.823(1) A, Z=4, R=0.055 for 673 observed Mo Kα data; [Au2(dmb)(CN)2]: space group P21/c, a=7.024(2), b=15.255(2), c=15.565(2) A, β=101.33(2), Z=4, R=0.050 for 2137 observed Mo Kα data; [Au2(tmb)(CN)2]: space group Pbcn, a=15.629(3), b=9.222(4), c=22.777(3), Z=8, R=0.036 for 1127 Mo Kα data. The intermolecular Au…Au separations are 3.568, 3.49-3.73 and 3.21 A for crystals of [Au(tBuNC)(CN)], [Au2(dmb)(CN)2] and [Au2(tmb)(CN)2], respectively. [Au2(tmb)2]2+ and [Au2(dmb)2]2+ have also been synthesized by the reaction of Au(I) with the diisocyanide ligand. Their UV-Vis spectra are compared and discussed.

A new luminescent d8–d8 dinuclear PtII polypyridyl complex [Pt2(2,2′: 6′,2″-terpyridine)2(Gua)]3+ is synthesised and characterized by X-ray crystallography; its spectroscopic and photoredox properties are investigated.

The complex [Pd2(dppm)2(CN)4][dppm = bis(diphenylphosphino)methane] displays an intense absorption band at 272 nm (Iµmax= 5.2 × 104 dm3 mol–1 cm–1) attributed to the dσ*→ pσ transition. Crystals of the complex are monoclinic, space group P21/n(no. 14, non-standard) with a= 11.476(2), b= 17.565(2), c= 13.964(2)A, β= 95.07(1)° and Z= 2. The measured intramolecular Pd ⋯ Pd distance is 3.276(1)A.

The X-ray structure and photoredox properties of [AuPt(µ-dppm)2(CN)2]+ which has a long-lived (18 µs in acetonitrile at room temperature) and emissive excited state are described.

The [Ag3(dppp)2(MeCN)2(ClO4)2]+ complex displays 1(dσ*→ pσ) transition at 288 nm and solid state photoluminescence at 467 nm; the Ag–Ag distances are 2.943–-3. 014 (2)A.

The particulate methane monooxygenase (pMMO) is known to be very difficult to study mainly due to its unusual activity instability in vitro. By cultivating Methylococcus capsulatus (Bath) under methane stress conditions and high copper levels in the growth medium, membranes highly enriched in the pMMO with exceptionally stable activity can be isolated from these cells. Purified and active pMMO can be subsequently obtained from these membrane preparations using protocols in which an excess of reductants and anaerobic conditions were maintained during membrane solubilization by dodecyl beta-D-maltoside and purification by chromatography. The pMMO was found to be the major constituent in these membranes, constituting 60-80% of total membrane proteins. The dominant species of the pMMO was found to consist of three subunits, alpha, beta, and gamma, with an apparent molecular mass of 45, 26, and 23 kDa, respectively. A second species of the pMMO, a proteolytically processed version of the enzyme, was found to be composed of three subunits, alpha', beta, and gamma, with an apparent molecular mass of 35, 26, and 23 kDa, respectively. The alpha and alpha' subunits from these two forms of the pMMO contain identical N-terminal sequences. The gamma subunit, however, exhibits variation in its N-terminal sequence. The pMMO is a copper-containing protein only and shows a requirement for Cu(I) ions. Approximately 12-15 Cu ions per 94-kDa monomeric unit were observed. The pMMO is sensitive to dioxygen tension. On the basis of dioxygen sensitivity, three kinetically distinct forms of the enzyme can be distinguished. A slow but air-stable form, which is converted into a "pulsed" state upon direct exposure to atmospheric oxygen pressure, is considered as type I pMMO. This form was the subject of our pMMO isolation effort. Other forms (types II and III) are deactivated to various extents upon exposure to atmospheric dioxygen pressure. Under inactivating conditions, these unstable forms release protons to the buffer (~10 H+/94-kDa monomeric unit) and eventually become completely inactive.

Emission from the intraligand 3(ππ*) and 3(dπ*)(dσ*) excited states has been observed in fluid solution and the solid state of [Pt2(dppm)2Cl(L)]ClO4[dppm = Ph2PCH2PPh2, L =(4-chlorophenyl)(4-pyridyl)-acetylene], the structure of which has been determined by X-ray crystallography.