Complex formation of silver(I) ion with a glucosinolate derivative: structural and mechanistic insights into myrosinase-mimicking C-S bond cleavage

2021 ◽  
Author(s):  
Laurenzo De Vera Alba ◽  
Tsubasa Hatanaka ◽  
Francisco Corpuz Franco Jr. ◽  
Masaki NOJIRI ◽  
Marissa NOEL ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Complex Formation ◽  
Bond Cleavage ◽  
Silver Complex ◽  
Mechanistic Studies

The crystal structure of an unprecedented silver complex of O-acetylsinigrin has shown chelating bonds of the sulfated thiohydroximate and an η2-bond of the ethylene moiety with Ag(I). Mechanistic studies on...

The Crystal Structure ofBacillus cereusPhosphonoacetaldehyde Hydrolase:  Insight into Catalysis of Phosphorus Bond Cleavage and Catalytic Diversification within the HAD Enzyme Superfamily†,‡

Biochemistry ◽  
2000 ◽  
Vol 39 (34) ◽  
pp. 10385-10396 ◽  
Author(s):  
Marc C. Morais ◽  
Wenhai Zhang ◽  
Angela S. Baker ◽  
Guofeng Zhang ◽  
Debra Dunaway-Mariano ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Bond Cleavage ◽  
Enzyme Superfamily ◽  
Insight Into

scholarly journals Crystal Structure of Vaccinia Viral A27 Protein Reveals a Novel Structure Critical for Its Function and Complex Formation with A26 Protein

2013 ◽  
Vol 9 (8) ◽  
pp. e1003563 ◽  
Author(s):  
Tao-Hsin Chang ◽  
Shu-Jung Chang ◽  
Fu-Lien Hsieh ◽  
Tzu-Ping Ko ◽  
Cheng-Tse Lin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Complex Formation ◽  
Novel Structure

scholarly journals Controlling Non-Native B12 Reactivity and Catalysis in the Transcription Factor CarH

2021 ◽  
Author(s):  
Xinhang Yang ◽  
Benjamin H. R. Gerroll ◽  
Yuhua Jiang ◽  
Amardeep Kumar ◽  
Yasmine S. Zubi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Vitamin B12 ◽  
Transcription Regulation ◽  
Bond Cleavage ◽  
Oxidative Addition ◽  
Mechanistic Studies ◽  
Organic Transformations ◽  
Carbon Bond ◽  
Wide Range ◽  
Hydride Elimination

Vitamin B12 derivatives catalyze a wide range of organic transformations, but B12-dependent enzymes are underutilized in biocatalysis relative to other metalloenzymes. In this study, we engineered a variant of the transcription factor CarH, called CarH*, that catalyzes styrene C-H alkylation with improved yield and selectivity relative to B12 itself. While the native function of CarH involves transcription regulation via AdoCbl Co(III)-carbon bond cleavage and β-hydride elimination to generate 4’,5’-didehydroadenosine, CarH*-catalyzed styrene alkylation proceeds via non-native oxidative addition and olefin addition coupled with a native-like β-hydride elimination. Mechanistic studies on this reaction echo findings from earlier studies on AdoCbl homolysis under strong cage conditions to suggest that CarH* can enable non-native radical chemistry with improved selectivity relative to B12 itself. These findings lay the groundwork for the development of B12-dependent enzymes as catalysts for a wide range of non-native transformations.

scholarly journals Calixarene-mediated assembly of a small antifungal protein

IUCrJ ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 238-247 ◽  
Author(s):  
Jimi M. Alex ◽  
Martin L. Rennie ◽  
Sylvain Engilberge ◽  
Gábor Lehoczki ◽  
Hajdu Dorottya ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Antifungal Activity ◽  
High Resolution ◽  
Complex Formation ◽  
Binding Site ◽  
Crystal Structures ◽  
Protein Assembly ◽  
Bidentate Ligand ◽  
Antifungal Protein ◽  
Protein Recognition

Synthetic macrocycles such as calixarenes and cucurbiturils are increasingly applied as mediators of protein assembly and crystallization. The macrocycle can facilitate assembly by providing a surface on which two or more proteins bind simultaneously. This work explores the capacity of the sulfonato-calix[n]arene (sclx n ) series to effect crystallization of PAF, a small, cationic antifungal protein. Co-crystallization with sclx4, sclx6 or sclx8 led to high-resolution crystal structures. In the absence of sclx n , diffraction-quality crystals of PAF were not obtained. Interestingly, all three sclx n were bound to a similar patch on PAF. The largest and most flexible variant, sclx8, yielded a dimer of PAF. Complex formation was evident in solution via NMR and ITC experiments, showing more pronounced effects with increasing macrocycle size. In agreement with the crystal structure, the ITC data suggested that sclx8 acts as a bidentate ligand. The contributions of calixarene size/conformation to protein recognition and assembly are discussed. Finally, it is suggested that the conserved binding site for anionic calixarenes implicates this region of PAF in membrane binding, which is a prerequisite for antifungal activity.

scholarly journals Structural analysis of point mutations at theVaccinia virusA20/D4 interface

2016 ◽  
Vol 72 (9) ◽  
pp. 687-691 ◽  
Author(s):  
Céline Contesto-Richefeu ◽  
Nicolas Tarbouriech ◽  
Xavier Brazzolotto ◽  
Wim P. Burmeister ◽  
Christophe N. Peyrefitte ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Structural Analysis ◽  
Complex Formation ◽  
Dna Polymerase ◽  
Point Mutations ◽  
Conformational Space ◽  
Uracil Dna Glycosylase ◽  
Dimerization Interface ◽  
Solvation Parameters

TheVaccinia viruspolymerase holoenzyme is composed of three subunits: E9, the catalytic DNA polymerase subunit; D4, a uracil-DNA glycosylase; and A20, a protein with no known enzymatic activity. The D4/A20 heterodimer is the DNA polymerase cofactor, the function of which is essential for processive DNA synthesis. The recent crystal structure of D4 bound to the first 50 amino acids of A20 (D4/A201–50) revealed the importance of three residues, forming a cation–π interaction at the dimerization interface, for complex formation. These are Arg167 and Pro173 of D4 and Trp43 of A20. Here, the crystal structures of the three mutants D4-R167A/A201–50, D4-P173G/A201–50and D4/A201–50-W43A are presented. The D4/A20 interface of the three structures has been analysed for atomic solvation parameters and cation–π interactions. This study confirms previous biochemical data and also points out the importance for stability of the restrained conformational space of Pro173. Moreover, these new structures will be useful for the design and rational improvement of known molecules targeting the D4/A20 interface.

I2/TBHP-Promoted Approach to α-Keto Esters from Trifluoromethyl β-Diketones and Alcohols via C–C Bond Cleavage

Synlett ◽  
2017 ◽  
Vol 28 (15) ◽  
pp. 2018-2023 ◽  
Author(s):  
Xiang Fang ◽  
Xueyan Yang ◽  
Tongle Shao ◽  
Jun Zhou ◽  
Chen Jin ◽  
...  
Keyword(s):  
Oxidative Coupling ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Coupling Reaction ◽  
Mechanistic Studies ◽  
Metal Free ◽  
Oxidation Pathway ◽  
Keto Esters ◽  
Oxidative Coupling Reaction

A metal-free oxidative coupling reaction of trifluoromethyl β-diketones with alcohols for the synthesis of α-keto esters in good to excellent yields has been developed. Preliminary mechanistic studies suggest that an I2/TBHP promoted sequential iodination, C–C bond cleavage, C–O bond formation and oxidation pathway is involved in this reaction.

Reaktionen koordinierter Liganden, III [1]. Stabilisierung von Dimenthyldiphosphen und Menthylphosphiniden als Brückenliganden in Metallcarbonylkomplexen / Reaction of Coordinated Ligands, III [1]. Stabilization of Dim enthyldiphosphene and Menthylphosphinidene as Bridging Ligands in Metal Carbonyl Complexes

1986 ◽  
Vol 41 (5) ◽  
pp. 629-639 ◽  
Author(s):  
Anna-Margarete Hinke ◽  
Axel Hinke ◽  
Wilhelm Kuchen ◽  
Wolfgang Hönle
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Complex Formation ◽  
Main Product ◽  
Metal Carbonyl ◽  
Crystal Structure Analysis ◽  
Carbonyl Complexes ◽  
Bridging Ligands ◽  
Metal Carbonyl Complexes ◽  
Chromium Compounds

Abstract Reduction of MentPBr2M(CO)5 1 (M = Cr, W) with magnesium in THF yields the diphos­phene complex (CO)5M(Ment)P=P(Ment)M(CO)5 2 as the main product. In addition, a phosphinidene complex, (CO)5M(Ment)PM(CO)5 (3) is also formed. The latter is obtained in larger amounts, if the reaction is carried out in the presence of M(CO)5THF. The proposed structures are confirmed by NMR and UV data as well as - in the case of the chromium compounds (2a, 3a) - by crystal structure analysis. Compound 2a is obtained only as the frans-isomer. The P-P distance in 2a (204.0 pm) indicates a double bond which does not participate in the complex formation. The P-Cr distance in 3a (average: 230.3 pm) is within the low est range found for this element combination. Reaction of 2a with LiAlH4 yields the diphosphane complex (CO)5CrMent(H)P-P(H)MentCr(CO)5 4 as a mixture of “meso” and “rac” diastereomers.

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