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Mitochondria and chloroplasts are of endosymbiotic origin. Their integration into cells entailed the development of protein translocons, partially by recycling bacterial proteins. We demonstrate the evolutionary conservation of the translocon component Tic22 between cyanobacteria and chloroplasts. Tic22 in Anabaena sp. PCC 7120 is essential. The protein is localized in the thylakoids and in the periplasm and can be functionally replaced by a plant orthologue. Tic22 physically interacts with the outer envelope biogenesis factor Omp85 in vitro and in vivo, the latter exemplified by immunoprecipitation after chemical cross-linking. The physical interaction together with the phenotype of a tic22 mutant comparable with the one of the omp85 mutant indicates a concerted function of both proteins. The three-dimensional structure allows the definition of conserved hydrophobic pockets comparable with those of ClpS or BamB. The results presented suggest a function of Tic22 in outer membrane biogenesis.
Background: Although Tic22 is involved in protein import into chloroplasts, the function in cyanobacteria is unknown.
Results: Cyanobacterial Tic22 is required for OM biogenesis, shares structural features with chaperones, and can be substituted by plant Tic22.
Conclusion: Tic22, involved in outer membrane biogenesis, is functionally conserved in cyanobacteria and plants.
Significance: The findings are important for the understanding of periplasmic protein transport.
Bis(N,N-diethyl-N′-benzoylselenoureato)lead(II) has been prepared and characterized by single-crystal structure analysis. Pb(C12H15N2OSe)2 crystallizes in the non-centrosymmetric orthorhombic space group Iba2. The cell parameters are a = 13.206(3), b = 20.542(4), c = 10.089(2) A and Z = 4. R = 0.025. The direction of the polar axis was determined unambig uously. Pb(II) is bidentally coordinated to two N,N-diethyl-N′-benzoylselenourea molecules. The coordination polyhedron is a distorted pseudo-trigonal bi-pyramid with one equatorial position occupied by an electron lone-pair. The Pb-Se and Pb-O bond lengths are 2.876(1) and 2.444(4) Å, respectively. In the crystal lattice, each Pb atom also shows interactions with two Se atoms of a neighboring molecule. The Pb-Se distance of that interaction is 3.643 Å.
With new X-ray data from a crystal of stoichiometric K0.33MoO3 the crystal structure of this compound was refined until R(anisotropic) = 0.023. The characteristic distortion of the Mo-O octahedra is discussed.
Crystals of [Al(C5H5N)4Cl2][AlCl4] are orthorhombic, Pna21, Z = 4, a = 18.522(7), b = 15.141(5), c = 9.593(3) Å, V = 2690(2) Å3 , Dc = 1.440 g/cm3 . The structure has been solved from 5968 diffractometer measured intensities and refined by full-matrix least squares to Rw(F) = 0.032. The crystal structure shows the complex to be trans-dichloro-tetrakis(pyridine)aluminium(III) tetrachloroaluminat(III). The mean trans Al-Cl-and trans Al-N-distances in the octahedron are 2.279(3) and 2.070(4) Å, respectively. Crystals of Al(C5H5N)3Cl3 are monoclinic, P21/c, Z = 4, a = 7.261(2), b = 29.961(4), c = 8.624(1) Å, β = 98.12(2)°, V -1857(1) Å3 , DC = 1.326 g/cm3 . The structure has been solved from 4707 diffractometer measured intensities and refined to Rw(F) = 0.028. The crystal structure shows octahedral complexes AlCl3·3 (C5H5N) with trans geometry. The Al-N-distance trans to chlorine (2.096(2) Å) is significantly longer than the two other Al-N-distances (mean 2.072(2) Å).
The title compound has been prepared by the reaction of N,N,N′-tris(trimethylsilyl)benzamidine with tantalum pentachloride in CH2Cl2 suspension, forming amber-coloured, moisturesensitive crystals, which were characterized by an X-ray structure determination. Space group P 21/n, Z = 2, 4895 observed independent reflexions, R = 0.059. Lattice dimensions (-65°C): a = 1165.2(6), b = 1335.4(6), c = 1629.0(7) pm, β = 93.23(4)°. The complex forms centrosymmetric molecules dimerized via chloro bridges TaCl2Ta with TaCl bond lengths of 247.2(2) and 277.1(2) pm, the longer one being in trans-position to the imido group, which can be formulated as [xxx] (bond lengths Ta=Ν = 183.5(8), C=N = 134(1) pm, bond angle TaNC = 162.7(7)°).
The title compounds Ph3PNPh · CuCl (1) and (Ph3P)2 N2 C4O2 (NMe) CuCl (2) have been prepared by the reactions of CuCl with the corresponding phosphoranimines Ph3PNPh and 2.3-bis(triphenylphosphoranylideneamino)maleic acid N-methylimide, respectively. Both com-plexes were characterized by their IR spectra as well as by crystal structure determinations.
Ph3PNPh · CuCl (1): space group P1, Z = 4, 3639 independent observed reflexions, R = 0.038. Lattice dimensions (18 °C): a = 1047.6; b = 1251.5; c = 1755 pm; α = 103.43°; β = 97.24°; γ = 101.30°. The compound forms monomeric molecules; the asymmetric unit contains two crystallo-graphically independent molecules. The CuCl molecule is bonded via the N atom of the phos-phoranimine. Bond lengths: Cu-N = 189 pm; Cu-CI = 209 pm; bond angle N - Cu - CI = 177°.
(Ph3P)2N2C4O2(NMe) · CuCl (2): space group Pbca, Z = 8, 5611 independent, observed reflexions, R = 0.069. Lattice dimensions (25 °C): a = 1224.3; b = 1962.5: c = 2994.0 pm. The compound forms monomeric molecules with the CuCl molecule bonded via one of the N atoms of the phosphoranimine groups. Bond lengths: Cu - N = 194 pm; Cu-CI = 212 pm; bond angle N-Cu -CI -175°.
Pyrazolyl-substituted 1,4-dihydroxybenzene and 1,4-dihydroxynaphthene derivatives have been synthesized by reaction of 1,4-benzoquinone and 1,4-naphthoquinone, respectively, with pyrazole. Cyclovoltammetric measurements have shown that 1,4-benzoquinone possesses the potential to oxidize 2-(pyrazol-1-yl)- and 2,5-bis(pyrazol-1-yl)-1,4-dihydroxybenzene. The 2,5-bis(pyrazol-1-yl)- 1,4-dihydroxybenzene reacts with air to give quantitatively black insoluble 2,5-bis(pyrazol-1-yl)-1,4- quinhydrone. Black crystals of 2,5-bis(pyrazol-1-yl)-1,4-quinhydrone suitable for X-ray diffraction were grown from methanol at ambient temperature (monoclinic C2/c). The poor yields of pyrazolylsubstituted 1,4-dihydroxybenzene and 1,4-dihydroxynaphthene derivatives can be explained by the formation of insoluble black quinhydrons in the reaction of benzoquinone and naphthoquinone with pyrazole. The dianions of 2-(pyrazol-1-yl)- and 2,5-bis(pyrazol-1-yl)-1,4-dihydroxybenzene react with oxygen to give the corresponding semiquinone anions. 2,5-Bis(pyrazol-1-yl)-1,4-benzoquinone shows two reversible one-electron reduction processes in cyclovoltammetric measurements, whereas pyrazolyl-substituted 1,4-dihdroxybenzene and -naphthene derivatives undergo irreversibile electrontransfer processes.
[MONCl3 · NC - C2Cl3]2 has been prepared by the reaction of MONCl3 with trichloromethyl isocyanidedichloride, CCl3NCCl2 , in CH2Cl2 suspension. The compound forms redbrown. mois-ture sensitive crystals, which were characterized by their IR spectrum as well as by a crystal structure determination (2482 independent observed reflexions, R = 0.048). Crystal data (-70 °C): Space group P21/c, Z = 2, a = 674.2(2); b = 2128.2(11); c = 786.0(4) pm: β = 102.81(3)°. [MONCl3 • NC-C2Cl3]2 forms centrosymmetric dimeric molecules via chloro bridges with Mo-Cl bond lengths of 240.7 and 276.0 pm. The longer MoCl bond of the MOCl2MO ring is caused by the trans influence of the nitride ligand; the MoN bond length of 167 pm corresponds with a triple bond. The 2,3,3-trichloroacrylnitrile ligand is bonded by its nitrogen atom with a bond length of Mo -N = 216 pm; the Mo-N≡C-C sequence is almost linear with a remarkable short C-C bond of 143.0 pm.
The title compound has been prepared from (PPh4)2[Mo2(O2C-Ph)4Cl2] and CCl4 in CH2Cl2 solution as moisture sensitive crystals, which are black in reflexion and yellow in transmission. (PPh4)2[Mo2(O2C-Ph)4Cl4] · 2 CH2Cl2 was characterized by a X-ray crystal structure determination (7873 observed independent reflexions. R = 0.048). It crystallizes in the space group P1̄ with one formula unit in the unit cell; the lattice constants are a = 1186.4; b = 1404.0; c = 1451.0 pm; α = 61.98°; β = 78.91°; γ = 78.26°. The structure consists of PPh4⊕ ions. CH2Cl2 molecules and centrosymmetric anions [Mo2(O2C-Ph)4Cl4]2⊝ containinga molybdenum d3 d3 unit with a relatively long Mo=Mo bond of 249.6 pm. The Mo≡Mo group is spanned in a chelate manner by four O atoms of two benzoate groups and by two further single O atoms of two further benzoate groups. Two terminal Cl atoms on each Mo atom complete the pentagonal bipyramidal coordination spheres about the Mo atoms.
Trimethylbromosilane and 3,4-lutidine form a 1:1 compound which is stable at room temperature. Single crystals of this compound can be isolated by sublimation. It crystallizes in the orthorhombic space group P 2121,21, with lattice constants a = 737,08(9) pm, b = 1295,7(1) pm, c = 1318,8(3) pm. The crystal structure was refined to Rw = 0,042 and proves an ionic structure.
Li6UO6 has a reversible phase transformation at 680°C and decomposes above about 850°C. At high pressure the low temperature modification becomes unstable because of an invariant point in the system Li2O—Li4UO5 at approximately 13 Kb and 620°C. β-Li6UO6 has a triclinic unit cell with a = 5.203, b= 5.520, c = 5.536 Å, α = 114.7, β = 120.7 and γ = 75.5°. The close relationship between the crystal structures of Li6TeO6 and Li6UO6 is also suggested from similar infrared spectra and from partial solid solution Li6UO6—Li6TeO6.
[Na-15-crown-5][WF5(NCl)] has been prepared as yellow crystals by the reaction of NaF with WC14(NCl) in the presence of 15-crown-5 in acetonitrile solution. The compound was characterized by its IR spectrum as well as by an X-ray structure determination. Crystal data: space group P 21/n, Z = 4 (2945 observed, independent reflexions, R = 0.035). Lattice dimensions at - 65 °C: a = 827.2(8); b = 1617.3(13); c = 1372.2(10) pm; β = 99.42(5)°. The com pound forms ion pairs, in which the sodium ion is seven-coordinated by the oxygen atoms of the crown ether m olecule, and by two fluorine ligands of the [WF5(NCl)]- unit with Na -F distances of 228.3(6) and 251.3(6) pm. The W ≡ N-Cl group of the anion is nearly linear (bond angle 176.1(5)°) with bond lengths WN = 173.3(6) and NCI = 162.2(7) pm.
[Na-15-Crown-5][MoF5(NCl)] has been prepared as yellow crystals by the reaction of NaF with MoF4(NCl) in the presence of 15-crown-5 in acetonitrile solution. The compound was characterized by its IR and 19F NMR spectra as well as by an X-ray structure determination. Crystal data: space group P21/n, Z = 4 (3736 observed, independent reflexions, R = 0.034). Lattice dimensions at -70 °C: a = 823.5(4). b = 1612.2(9), c = 1383.4(8), β = 99.35(3)°. The compound forms ion pairs, in which the sodium ion is seven-coordinated by the oxygen atoms of the crown ether molecule and by two fluorine ligands of the [MoF5(NCl)]- unit with Na-F distances of 228.3 and 249.6 pm. The Mo=N-Cl group of the anion is nearly linear (bond angle 175.8°) with bond lengths MoN = 172.9 and NCl = 161.8 pm.
[η5-CpMCl4] (M = Nb, Ta) reacts with E(SiMe3)2 (E = S, Se) to form different multinuclear clusters. The cation [Cp8Ta6S10]2+ (1) consists of a planar Ta2S2-ring of which each Ta is coordi-nated to two Cp2TaS2-fragments. [Cp4Ta4S13] (3) can be derived from [Cp3Ta3S7Cl2] (2) by addition of a CpTaS6-unit to a triangle of Ta-atoms bridged by S- and S2-ligands. The niobium atoms in [Cp3Nb3Se5Cl2] (4) arrange in a chain structure with Nb coordination numbers varying from 4-6.
W2NCl7 has been prepared by the reaction of tungsten pentachloride with the bromide of Millon's base, [Hg2N]Br, in boiling CCl4. The product forms a dark brown, moisture sensitive crystal powder (μeff = 0.7 B.M. at 21 °C). With phosphoryl chloride, the complex W2NCl7·2 POCl3 is formed. The reaction with chlorine leads to the mixed-valenced W(V)/W(VI) complex W2NCl8 (μeff = 0.5 B.M. at 22 °C), which reacts with tetraphenylphosphonium chloride in CH2Cl2 to form (PPh4)2[W2NCl10] ·2CH2Cl2. The reactions of W2NCl7 with PPh4Cl in molar ratios in CH2Cl2 solution lead to several complexes; one of them was identified bv X-ray diffraction methods to be (PPh4)2[W3Cl9(μ3-N)(0)(μ2-NCl)]2 ·1,5 CH2Cl2, which forms black crystals. The compound crystallizes monoclinically in the space group P21/n with two formula units per unit cell (7318 observed, independent reflexions, R = 0.083). The lattice dimensions are (20 °C): a = 994.4; b = 2673; c = 1518.2 pm; β = 101.00°. The compound consists of PPh4⊕ cations and centrosymmetric anions [W3Cl9(μ3-N)(O)(μ2-NCl)]22⊕. The tungsten atoms form a scalene triangle with WW bond lengths of 282 and 278 pm, respectively. The hypothenuse of this triangle is a nearly linear W - N -W bridge with WN distances of 199 and 182 pm. One of the WW edges is bridged by a μ-NCI group with WN bond lengths of 196 und 189 pm. respectively.
Kristallstruktur von 1,1-Dichlor-3,5-diphenyl-4-H-1,2,4,6-λ4-selenatriazin, SeCl2C2N3H(C6H5)2
(1989)
The title compound has been prepared as a byproduct of the reaction of Se2Cl2 with Ν,Ν,N′-Tris(trimethylsilyl)benzamidine in CH2Cl2 solution. [SeCl2(HNC2N2Ph2)]2 was characterized by an X-ray structure determination. Space group P21/n, Z = 2, 2979 observed independent reflexions, R = 0.032. Lattice dimensions (-65 °C): a = 1050.1(4), b = 1018.9(4), c = 1402.1(6) pm; β = 99.78(3)°. The compound forms centrosymmetric dimeric molecules with SeCl2Se bridges (bond lengths 241.6(1) and 339.3(1) pm), the selenium atoms being members of nearly planar [xxx] selenatriazine rings with Se—N bond lengths of 182.2(2) and 181.5(2) pm.
The title compound has been prepared by the reaction of N-trimethylsilyl-iminotriphenylphos-phorane with copper(II) chloride in boiling CCl4 /C2H5OH, and forms moisture sensitive crystals, which are green in transmittance and black in reflexion. [Me3SiNPPh3 · CuCl2 ] 2 was characterized by its IR spectrum as well as by a crystal structure determination (4197 observed, independent reflexions, R = 0.049). The lattice dimensions are at 20 °C: a = 1102.7. b = 1407.3. c = 1560.2 pm; β = 94.27°; space group P21/n with two formula units in the unit cell. The complex consists of centrosymmetric, dimeric molecules with a planar Cu2 Cl2 ring (Cu-CI bond lengths 229 and 231 pm). A terminally bonded CI atom (Cu-CI = 221 pm) and the N atom of the Me3SiNPPh3 ligand (Cu-N = 198.5 pm) complete the coordination number four of the nearly planar surroundings of the Cu atoms.
Cp2TiSe5 has been prepared by the reaction of trim ethyltetradecylammonium-polyselenide with Cp2TiCl2 in ethanol solution and subsequent extraction of the dry residue with dichloromethane. Cp2TiSe5 crystallizes in the space group P1 with two formula units in the unit cell (2559 observed, independent reflexions, R = 0.074). The cell dimensions are a = 808.6, b = 822.6, c = 1190.7 pm, α - 96.28°, β - 106.06°, γ = 108.78°. The structure consists of discrete Cp2TiSe5 molecules with the TiSe5, ring in the chair conformation.
Triphenylmethylphosphonium nitrite and formate have been prepared by the reaction of [PPh3Me]I with silver nitrite, and lead formate, respectively, in aqueous solutions. [PPh3Me]NO2 (1) forms pale yellow crystals, and [PPh3Me]HCO2·H2O (2) forms white crystals. Both compounds are soluble in water, ethanol, and dichloromethane. In moist air 2 is hydrated to yield [PPh3Me]HCO2·2H2O (3). The compounds were characterized by their IR spectra, 1 and 2 also by X-ray crystal structure determinations.
[PPh3Me]NO2 (1): space group P21/n, Z = 4, 2088 independent observed reflexions, R = 0.062. Lattice dimensions (20 °C): a = 914.7(3), b = 1887.5(9), c = 1080.0(4) pm, β = 110.29(3)°. The compound consists of PPh3Me+ ions and NO2- anions with bond lengths of 114.2(6) pm and a bond angle of 124.1(7)°.
[PPh3Me]HCO2·H2O (2): space group P21/n, Z = 4, 2973 independent observed reflexions, R = 0.069. Lattice dimensions (-20 °C): a = 931(2), b = 1558(3), c = 1281(2) pm, β = 105.9(1)°. The compound consists of PPh3Me+ ions and formate anions which form centrosymmetric dimeric units [HCO2·H2O]22- through hydrogen bridges of the water molecules. Bond lengths CO 122.4(4) and 120.9(4) pm. bond angle OCO 129.9(4)°.
Host cell invasion by the facultative intracellular pathogen Listeria monocytogenes requires the invasion protein InlB in many cell types. InlB consists of an N-terminal internalin domain that binds the host cell receptor tyrosine kinase Met and C-terminal GW domains that bind to glycosaminoglycans (GAGs). Met binding and activation is required for host cell invasion, while the interaction between GW domains and GAGs enhances this effect. Soluble InlB elicits the same cellular phenotypes as the natural Met ligand hepatocyte growth factor/scatter factor (HGF/SF), e.g. cell scatter. So far, little is known about the central part of InlB, the B-repeat. Here we present a structural and functional characterization of the InlB B-repeat. The crystal structure reveals a variation of the β-grasp fold that is most similar to small ubiquitin-like modifiers (SUMOs). However, structural similarity also suggests a potential evolutionary relation to bacterial mucin-binding proteins. The B-repeat defines the prototype structure of a hitherto uncharacterized domain present in over a thousand bacterial proteins. Generally, this domain probably acts as a spacer or a receptor-binding domain in extracellular multi-domain proteins. In cellular assays the B-repeat acts synergistically with the internalin domain conferring to it the ability to stimulate cell motility. Thus, the B-repeat probably binds a further host cell receptor and thereby enhances signaling downstream of Met.