A Single Atom Change Facilitates the Membrane Transport of Green Fluorescent Proteins in Mammalian Cells

Direct delivery of proteins into mammalian cells is a challenging problem in biological and biomedical applications. The most common strategies for the delivery of proteins into the cells include the use of cell‐penetrating peptides or supercharged proteins. Herein, we show for the first time that a single atom change, hydrogen to halogen, at one of the tyrosine residues can increase the cellular entry of ～28 kDa green fluorescent protein (GFP) in mammalian cells. The protein uptake is facilitated by a receptor‐mediated endocytosis and the cargo can be released effectively into cytosol by co‐treatment with the endosomolytic peptide ppTG21.     

High-PL efficiency of polyaniline using various dopants

Polyaniline (PANI) was doped with hydrochloric acid (HCl), succinic acid (C₄H₆O₄) and sulphuric acid (H₂SO₄) by chemical oxidation method. The samples were characterized by using various techniques such as XRD, photoluminescence IR and UV spectroscopy. FTIR study confirmed the presence of dopant molecules in the molecular structure. UV spectra revealed that absorption peaks at 350 nm and 600 nm are due to π–π* transition of polyaniline. The strong band at 600 nm showed extension of polymer chains in the prepared samples. XRD pattern confirmed the amorphous nature of polymer samples. The photoluminescence (PL) spectrum shows good emission at 490 nm. The intensity of photoluminescence depends upon the dopants nature.     

Crystal structure of 3‐hydroxy methyl 4,6‐dimethoxy‐9‐phenylsulfonyl‐carbazole

The crystal structure of 3‐Hydroxy methyl 4,6‐dimethoxy‐9‐phenylsulfonyl‐carbazole. (C₂₁H₁₉NO₅S) has been determined [CCDC 194425]. The compound crystallizes from methanol in the monoclinic system, space group I2/c, with unit cell parameters: a = 20.498(2), b = 9.258(2), c = 21.866(3)Å, β = 116.450(10)°, Z = 8, V = 3715.2(10)ų. The crystal structure was solved by direct methods and refined by full‐matrix least squares to a final R‐value of 0.050 with 3508 unique reflections. The planar carbazole ring fragment is inclined at an angle of 79.9(1)° to the phenylsulfonyl group. The sum of the angle about N is 351.6(2)°. The atoms linked to the central hexavalent S atom are arranged in a tetrahedral configuration with the larger deviations in the O‐SO angles [O1‐S‐O2 = 119.7(2)°] and the O1‐S‐N and O2‐S‐N angles [106.1(2) and 106.9(1)°, respectively].     

Crystal and Molecular Structure of 4-methoxy-carbonyl methyl-2,9-bis(phenylsulfonyl)-1,2,3,4-tetrahydro β-carboline : benzene solvate

The crystal structure of the title compound has been determined from X-ray diffraction data. The compound crystallizes from benzene in the monoclinic system, space group P2₁/a, with unit cell parameters: a = 12.676(2), b = 20.333(3), c = 12.947(2) Å, β = 113.12(1)°, Z = 4, V = 3069.0(8) ų. The trial structure was determined by direct methods and refined to a final R-index of 0.044. The six-membered heterocyclic ring adopts half-chair conformation. Of the two phenylsulfonyl groups, the one substituted at the indole nitrogen (N1) is equatorial, while the other (at N2) is axial. The methyl acetate group is approximately perpendicular to the β-carboline moiety.     

Crystal Structure of 9-benzenesulfonyl-1-keto-3-thia-1,2,3,4-tetrahydrocarbazole

The crystal structure of 9-benzenesulfonyl-1-keto-3-thia-1,2,3,4-tetrahydrocarbazole (C₁₇H₁₃NO₃S₂), has been determined. The compound forms crystals of parallelopiped shape and crystallizes in triclinic space group P1 with cell dimensions a = 7.887(6), b = 9.210(6), c = 11.280(5) Å, a = 106.47(5), b = 75.72(6), g = 101.57(4), V = 753.9(8) ų, Z = 2, D_cal = 1.513 Mgm^-3 and T = 298 K. The structure was solved by direct methods and refined by full-matrix least-squares to a final R value of 0.066 with 2861 unique reflections. The heterocyclic six-membered ring of the carbazole moiety adopts half-boat conformation. The phenylsulfonyl substituent occupies equatorial position at N and is inclined by an angle of 71.2(5) to the carbazole moiety. The N atom lies 0.162(3)Å out of the plane of the three atoms bonded to it. The S1 atom possesses usual distorted tetrahedral geometry.     

Crystal Structure of Dimeric Cu(II) Complex {μ,μ'‐acetato O,O bis [N‐salicylidene‐2‐amino‐pyridine‐methanolato N,N,O]} : perchlorate

The crystal structure of the title complex has been solved using X‐ray diffraction data.The compound crystallizes from aqueous ethanol solvent in the triclinic system, space group P‐1, with unit cell parameters: a = 8.9532(1), b = 12.7423(3), c = 14.9012(3) Å, α = 73.767(1), β = 75.322(1), γ = 77.496(1)°, Z = 2, V = 1559.4(5) ų. The trial structure was determined by automated Patterson methods and subsequent difference Fourier techniques using DIRDIF98 and refined to a final R‐factor of 0.064. The copper ion Cu1 adopts a (4+1) square‐pyramidal geometry defined by the tridentate N‐salicylidimine dianions and the neutral monodentate pyridine ligand in the basal plane. The apical position is occupied by a solvent methanol molecule at a distance of 2.341(4) Å. The copper Cu2 adopts a square‐planar geometry.     

Crystal Structure of t‐boc‐O‐benzyl‐L‐tyrosyl‐D‐alanyl‐L‐(O‐benzyl)‐glutamate : monohydrate

The crystal structure of a tripeptide, t‐boc‐O‐benzyl‐L‐tyrosyl‐D‐alanyl‐L‐(O‐benzyl)‐glutamate has been determined by direct methods, and refined by full‐matrix least squares procedures to a final R‐index of 0.060. The peptide conformation corresponds to a reverse turn — Type II , stabilized by a 4 — 1 N‐H...O hydrogen bond, with the amide proton also forming a bifurcated hydrogen bond to an oxygen atom from the C‐terminus of a neighbouring molecule.