scholarly journals Crystal Structure of the Streptomyces coelicolor Sortase E1 Transpeptidase Provides Insight into the Binding Mode of the Novel Class E Sorting Signal

PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0167763 ◽  
Author(s):  
Michele D. Kattke ◽  
Albert H. Chan ◽  
Andrew Duong ◽  
Danielle L. Sexton ◽  
Michael R. Sawaya ◽  
...  
2014 ◽  
Vol 70 (a1) ◽  
pp. C307-C307
Author(s):  
Bernd Kuhn ◽  
Jörg Benz ◽  
Michael Greif ◽  
Alfred Engel ◽  
Harald Sobek ◽  
...  

Human β-galactoside α-2,6 sialyltransferase I (ST6Gal-I) establishes the final glycosylation pattern of many glycoproteins by transferring a sialyl moiety to a terminal galactose. Complete sialylation of therapeutic immunoglobulins is essential for their anti-inflammatory activity and for protein stability. However, a complete glycan tree is difficult to achieve in vitro due to limited activity of ST6Gal-I for some galactose acceptors. No structural information on ST6Gal-I that could help to improve the enzymatic properties of ST6Gal-I for biotechnological purposes was previously available. We describe the crystal structure of human ST6Gal-I, which allows rationalizing the inhibitory activity of cytosine-based nucleotides. ST6Gal-I differs from related sialyltransferases by several large insertions and deletions that determine its regio- and substrate specificity. Excitingly, a large glycan binds to the active site in a catalytically competent orientation, representing the general binding mode of any substrate glycoprotein. This binding mode also rationalizes why some galactose acceptors are incompletely sialylated. Comparison with a bacterial sialyltransferase lends first insight into the Michaelis complex. The results support an SN2 mechanism with inversion of configuration at the sialyl residue and suggest substrate-assisted catalysis with a charge relay mechanism that bears conceptual similarity to serine proteases.


2015 ◽  
Vol 71 (9) ◽  
pp. 1114-1119 ◽  
Author(s):  
Sheng Ding ◽  
Ruiqing Zhou ◽  
Yaqin Zhu

The 14-3-3 proteins are a family of highly conserved proteins that play key roles in many cellular processes. The tumour suppressor LKB1 regulates cell polarity, cell growth and energy metabolism. 14-3-3 proteins bind to LKB1 and suppress its functions. Previously, preliminary crystallographic data for the 14-3-3ζ–LKB1 fusion protein have been reported. Here, the crystal structure of this fusion protein was solved and a novel potential binding mode of 14-3-3 to its ligands was found.


2019 ◽  
Author(s):  
Victoria A. Ternes ◽  
Hannah A. Morgan ◽  
Austin P. Lanquist ◽  
Michael P. Murray ◽  
Bradley Wile

Herein we report the preparation of a series of Ru(II) complexes featuring alpha-iminopyridine ligands bearing thioether functionality (NNS<sup>R</sup>, where R = Me, CH<sub>2</sub>Ph, Ph). Metallation using (<i>p</i> cymene)RuCl dimer permits access to (k<sup>2</sup>-N,N)Ru complexes in which the thioether moiety remains uncoordinated. In the presence of a strong field ligand such as acetonitrile or triphenylphosphine, the p-cymene moiety is displaced, and the ligand adopts a k<sup>3</sup>-N,N,S binding mode. These complexes are characterized using a combination of solution and solid state methods, including the crystal structure of [(NNS<sup>Me</sup>)Ru(NCMe)<sub>2</sub>Cl]Cl. The k<sup>2</sup>-N,N Ru(II) complexes are shown to serve as efficient precatalysts for the oxidation of sec-phenethyl alcohol at 5 mol% loadings, using a variety of external oxidants and solvents. The complex bearing an S-Ph donor was found to be the most active of those surveyed, suggesting that the thioether donor plays an active role in catalyst speciation for this transformation.


Author(s):  
Matthew Lewis

‘He was deaf to the murmurs of conscience, and resolved to satisfy his desires at any price.’ The Monk (1796) is a sensational story of temptation and depravity, a masterpiece of Gothic fiction and the first horror novel in English literature. The respected monk Ambrosio, the Abbot of a Capuchin monastery in Madrid, is overwhelmed with desire for a young girl; once having abandoned his monastic vows he begins a terrible descent into immorality and violence. His appalling fall from grace embraces blasphemy, black magic, torture, rape, and murder, and places his very soul in jeopardy. Lewis’s extraordinary tale drew on folklore, legendary ghost stories, and contemporary dread inspired by the terrors of the French Revolution. Its excesses shocked the reading public and it was condemned as obscene. The novel continues to beguile and shock readers today with its gruesome catalogue of iniquities, while at the same time giving a profound insight into the deep anxieties experienced by British citizens during one of the most turbulent periods in the nation’s history.


1993 ◽  
Vol 57 (386) ◽  
pp. 157-164 ◽  
Author(s):  
Mitsuyoshi Kimata

AbstractThe crystal structure of KBSi3O8 (orthorhombic, Pnam, with a = 8.683(1), b = 9.253(1), c = 8.272(1) Å,, V = 664.4(1) Å3, Z = 4) has been determined by the direct method applied to 3- dimensional rcflection data. The structure of a microcrystal with the dimensions 20 × 29 × 37 μm was refined to an unweightcd residual of R = 0.031 using 386 non-zero structure amplitudes. KBSi3O8 adopts a structure essentially different from recdmergneritc NaBSi3O8, with the low albite (NaAlSi3O8) structure, and isotypic with danburite CaB2Si2Os which has the same topology as paracelsian BaAl2Si2O8. The chenfical relationship between this sample and danburitc gives insight into a new coupled substitution; K+ + Si4+ = Ca2+ + B3+ in the extraframework and tetrahedral sites. The present occupancy refinement revealed partial disordering of B and Si atoms which jointly reside in two kinds of general equivalent points, T(1) and T(2) sites. Thus the expanded crystal-chemical formula can be written in the form K(B0.44Si0.56)2(B0.06Si0.94)2O8The systematic trend among crystalline compounds with the M+T3+T4+3O8 formula suggests that they exist in one of four structural types; the feldspar structures with T3+/T4+ ordered and/or disordered forms, and the paracelsian and the hollandite structures.


2021 ◽  
Vol 103 (3) ◽  
Author(s):  
Silvie Maskova-Cerna ◽  
Alexandre Kolomiets ◽  
Jiri Prchal ◽  
Itzhak Halevy ◽  
Volodymyr Buturlim ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4067
Author(s):  
Giovanni Ricci ◽  
Giuseppe Leone ◽  
Giorgia Zanchin ◽  
Benedetta Palucci ◽  
Alessandra Forni ◽  
...  

Some novel cobalt diphenylphosphine complexes were synthesized by reacting cobalt(II) chloride with (2-methoxyethyl)diphenylphosphine, (2-methoxyphenyl)diphenylphosphine, and 2-(1,1-dimethylpropyl)-6-(diphenylphosphino)pyridine. Single crystals suitable for X-ray diffraction studies were obtained for the first two complexes, and their crystal structure was determined. The novel compounds were then used in association with methylaluminoxane (MAO) for the polymerization of 1,3-butadiene, and their behavior was compared with that exhibited in the polymerization of the same monomer by the systems CoCl2(PnPrPh2)2/MAO and CoCl2(PPh3)2/MAO. Some significant differences were observed depending on the MAO/Co ratio used, and a plausible interpretation for such a different behavior is proposed.


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