Synthesis and crystal structures of Ni(II), Cu(II) and μ-oxo-Fe(III) complexes of a salen type ligand: Mononuclear versus multinuclear complex formation

Polyhedron ◽  
2009 ◽  
Vol 28 (17) ◽  
pp. 3804-3810 ◽  
Author(s):  
Linah N. Rusere ◽  
Tamila Shalumova ◽  
Joseph M. Tanski ◽  
Laurie A. Tyler
Keyword(s):  
Complex Formation ◽  
Crystal Structures ◽  
Multinuclear Complex

scholarly journals Crystal structures of an E1–E2–ubiquitin thioester mimetic reveal molecular mechanisms of transthioesterification

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lingmin Yuan ◽  
Zongyang Lv ◽  
Melanie J. Adams ◽  
Shaun K. Olsen
Keyword(s):  
Complex Formation ◽  
Crystal Structures ◽  
Molecular Mechanisms ◽  
Conformational State ◽  
Biochemical Data ◽  
Conformational States ◽  
Product Release ◽  
Closed Conformation ◽  
Open Conformation ◽  
Conjugating Enzymes

AbstractE1 enzymes function as gatekeepers of ubiquitin (Ub) signaling by catalyzing activation and transfer of Ub to tens of cognate E2 conjugating enzymes in a process called E1–E2 transthioesterification. The molecular mechanisms of transthioesterification and the overall architecture of the E1–E2–Ub complex during catalysis are unknown. Here, we determine the structure of a covalently trapped E1–E2–ubiquitin thioester mimetic. Two distinct architectures of the complex are observed, one in which the Ub thioester (Ub(t)) contacts E1 in an open conformation and another in which Ub(t) instead contacts E2 in a drastically different, closed conformation. Altogether our structural and biochemical data suggest that these two conformational states represent snapshots of the E1–E2–Ub complex pre- and post-thioester transfer, and are consistent with a model in which catalysis is enhanced by a Ub(t)-mediated affinity switch that drives the reaction forward by promoting productive complex formation or product release depending on the conformational state.

Crystal structures of nickel(II) and copper(Il)-Schiff-bases complexes with tetramic and tetronic acid subunits

1994 ◽  
Vol 209 (12) ◽  
Author(s):  
G. Reck ◽  
B. Schulz ◽  
A. Zschunke ◽  
O. Tietze ◽  
J. Haferkorn
Keyword(s):  
Complex Formation ◽  
Water Molecule ◽  
Crystal Structures ◽  
Schiff Bases ◽  
Water Molecules ◽  
Ligand Molecule ◽  
Tetragonal Pyramid ◽  
Space Group ◽  
Tetronic Acid ◽  
Oxygen Ligand

AbstractN,N′-ethylene-bis-(tetronic-acid-3-formiminato)-copper(II)/K1 crystallizes in space groupN,N′-ethylene-bis-(tetronic-acid-3-formiminato)-nikkel(II)/K2 crystallizes in space groupN,N′-ethylene-bis-(1,5,5-trimethyltetramic-acid-3-formiminato)-copper(II)/K3 crystallizes in space groupIn K1 and K3 copper is coordinated by two nitrogen and two oxygen atoms of the ligand molecule as well as by one water molecule on top of a tetragonal pyramid. In K2 two water molecules are included in the complex formation. These and two nitrogen as well as two oxygen ligand atoms form a nearly regular octahedron.

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 Multinuclear Complex Formation between Ca(II) and Gluconate Ions in Hyperalkaline Solutions

2014 ◽  
Vol 48 (12) ◽  
pp. 6604-6611 ◽  
Author(s):  
Attila Pallagi ◽  
Éva G. Bajnóczi ◽  
Sophie E. Canton ◽  
Trudy Bolin ◽  
Gábor Peintler ◽  
...  
Keyword(s):  
Complex Formation ◽  
Multinuclear Complex

Complex Formation between a Nucleobase and Tetracyanoquinodimethane Derivatives: Crystal Structures and Transport Properties of Charge-Transfer Solids of Cytosine

2008 ◽  
Vol 81 (3) ◽  
pp. 331-344 ◽  
Author(s):  
Tsuyoshi Murata ◽  
Gunzi Saito ◽  
Kazukuni Nishimura ◽  
Yuichiro Enomoto ◽  
Genki Honda ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Complex Formation ◽  
Transport Properties ◽  
Crystal Structures
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