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C60H51N16O16Cl3Co2, monoclinic, P21/ n (no. 14), a = 35.652(4) Å, b = 14.1314(16) Å, c = 25.141(3) Å, β = 105.113(2)°, V = 12228(3) Å3, Z = 8, Rgt( F) = 0.0651, wRref( F2) = 0.1663, T = 103(2) K. [ABSTRACT FROM AUTHOR]

Membrane proteins play key roles in many fundamental functions in cells including ATP synthesis, ion and molecule transporter, cell signalling and enzymatic reactions, accounting for ~30% genes of whole genomes. However, the hydrophobic nature of membrane proteins frequently hampers the progress of structure determination. Detergent screening is the critical step in obtaining stable detergent-solubilized membrane proteins and well-diffracting protein crystals. Fluorescence Detection Size Exclusion Chromatography (FSEC) has been developed to monitor the extraction efficiency and monodispersity of membrane proteins in detergent micelles. By tracing the FSEC profiles of GFP-fused membrane proteins, this method significantly enhances the throughput of detergent screening. However, current methods to acquire FSEC profiles require either an in-line fluorescence detector with the SEC equipment or an off-line spectrofluorometer microplate reader. Here, we introduce an alternative method detecting the absorption of GFP (FA-SEC) at 485 nm, thus making this methodology possible on conventional SEC equipment through the in-line absorbance spectrometer. The results demonstrate that absorption is in great correlation with fluorescence of GFP. The comparably weaker absorption signal can be improved by using a longer path-length flow cell. The FA-SEC profiles were congruent with the ones plotted by FSEC, suggesting FA-SEC could be a comparable and economical setup for detergent screening of membrane proteins. [ABSTRACT FROM AUTHOR]

C26H42N4O15Ni, triclinic, P1̅ (no. 2), a = 6.9662(8) Å, b = 9.0381(10) Å, c = 13.4863(15) Å, α = 71.430(1)°, β = 79.568(1)°, γ = 85.621(1)°, V = 791.44(15) Å3, Z = 1, Rgt (F) = 0.0377, wRref (F2 ) = 0.1312, T = 293(2) K. [ABSTRACT FROM AUTHOR]

The article discusses the crystal structure of poly[(.3-4-(4-oxopyridin-1(4H)-yl)phtalato-κ4O,O':O'':O''')-(μ2-2-carboxy-5-(4-oxopyridin-1(4H)-yl)benzoato-κ3O,O':O'')samarium(III)]. Topics discussed include its physical properties, chemical formula, chemical structure, and its atomic coordinates and displacement parameters.

The topology of helix-bundle membrane proteins provides low-resolution structural information with regard to the number and orientation of membrane-spanning helices, as well as the sidedness of intra/extra-cellular domains. In the past decades, several strategies have been developed to experimentally determine the topology of membrane proteins. However, generally, these methods are labour-intensive, time-consuming and difficult to implement for quantitative analysis. Here, we report a novel approach, site-directed alkylation detected by in-gel fluorescence (SDAF), which monitors the fluorescent band shift caused by alkylation of the EGFP-fused target membrane protein bearing one single introduced cysteine. In-gel fluorescence provides a unique readout of target membrane proteins with EGFP fusion from non-purified samples, revealing a distinct 5 kDa shift on SDS-PAGE gel due to conjugation with mPEG-MAL-5K. Using the structurally characterised bile acid transporter ASBTNM as an example, we demonstrate that SDAF generates a topology map consistent with the crystal structure. The efficiency of mPEG-MAL-5K modification at each introduced cysteine can easily be quantified and analysed, providing a useful tool for probing the solvent accessibility at a specific position of the target membrane protein. [ABSTRACT FROM AUTHOR]

The article discusses the crystal structure of hexaaquazinc(II) bis(6-methyl-2-oxo-1,2- dihydroxopyridine-4-carboxylate, whose chemical formulae is C14H24N2O12Zn. Topics discussed include its physical properties, chemical formula, chemical structure, and its atomic coordinates and displacement parameters.