scholarly journals Do interhelical side chain-backbone hydrogen bonds participate in formation of leucine zipper coiled coils?

1991 ◽  
Vol 88 (21) ◽  
pp. 9488-9492 ◽  
Author(s):  
A. Tropsha ◽  
J. P. Bowen ◽  
F. K. Brown ◽  
J. S. Kizer
Keyword(s):  
Hydrogen Bonds ◽  
Leucine Zipper ◽  
Coiled Coils ◽  
Side Chain

scholarly journals Bioelectrocatalytic hydrogels from electron-conducting metallopolypeptides coassembled with bifunctional enzymatic building blocks

2008 ◽  
Vol 105 (40) ◽  
pp. 15275-15280 ◽  
Author(s):  
Ian R. Wheeldon ◽  
Joshua W. Gallaway ◽  
Scott Calabrese Barton ◽  
Scott Banta
Keyword(s):  
Polyphenol Oxidase ◽  
Building Block ◽  
Leucine Zipper ◽  
Electrical Contact ◽  
Building Blocks ◽  
Coiled Coils ◽  
Biofuel Cell ◽  
Random Coil ◽  
Catalytic Current ◽  
And Function

Here, we present two bifunctional protein building blocks that coassemble to form a bioelectrocatalytic hydrogel that catalyzes the reduction of dioxygen to water. One building block, a metallopolypeptide based on a previously designed triblock polypeptide, is electron-conducting. A second building block is a chimera of artificial α-helical leucine zipper and random coil domains fused to a polyphenol oxidase, small laccase (SLAC). The metallopolypeptide has a helix–random-helix secondary structure and forms a hydrogel via tetrameric coiled coils. The helical and random domains are identical to those fused to the polyphenol oxidase. Electron-conducting functionality is derived from the divalent attachment of an osmium bis-bipyrdine complex to histidine residues within the peptide. Attachment of the osmium moiety is demonstrated by mass spectroscopy (MS-MALDI-TOF) and cyclic voltammetry. The structure and function of the α-helical domains are confirmed by circular dichroism spectroscopy and by rheological measurements. The metallopolypeptide shows the ability to make electrical contact to a solid-state electrode and to the redox centers of modified SLAC. Neat samples of the modified SLAC form hydrogels, indicating that the fused α-helical domain functions as a physical cross-linker. The fusion does not disrupt dimer formation, a necessity for catalytic activity. Mixtures of the two building blocks coassemble to form a continuous supramolecular hydrogel that, when polarized, generates a catalytic current in the presence of oxygen. The specific application of the system is a biofuel cell cathode, but this protein-engineering approach to advanced functional hydrogel design is general and broadly applicable to biocatalytic, biosensing, and tissue-engineering applications.

scholarly journals Diethyl (E)-2,3-bis[(E)-(2-methyl-2-phenylhydrazin-1-ylidene)methyl]but-2-enedioate

2014 ◽  
Vol 70 (6) ◽  
pp. o723-o723
Author(s):  
Peng Liu ◽  
Libin Yuan ◽  
Xiuqing Song ◽  
Hong Yan
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Phenyl Ring ◽  
Side Chain ◽  
Dihedral Angles ◽  
Inversion Symmetry ◽  
Compound C ◽  
Corrugated Sheets ◽  
Major Conformation

The complete molecule of the title compound, C24H28N4O4, is generated by crystallographic inversion symmetry. The ethyl side chain is disordered over two sets of sites in a 0.57 (4):0.43 (4) ratio. The dihedral angles between the methylidene group and the phenyl ring and ester side chain (major conformation) are 7.61 (8) and 86.95 (8)°, respectively. In the crystal, molecules are linkedviaC—H...O hydrogen bonds, forming corrugated sheets lying parallel to (010).

scholarly journals Crystal structures of μ-oxalato-bis[azido(histamine)copper(II)] and μ-oxalato-bis[(dicyanamido)(histamine)copper(II)]

2015 ◽  
Vol 71 (11) ◽  
pp. 1379-1383 ◽  
Author(s):  
Chen Liu ◽  
Khalil A. Abboud
Keyword(s):  
Hydrogen Bonds ◽  
Copper Complexes ◽  
Copper Ions ◽  
Side Chain ◽  
Dinuclear Complexes ◽  
Compound I ◽  
Coordination Site ◽  
Oxalate Ligand ◽  
Compound Ii ◽  
Neighboring Molecule

The title compounds, μ-oxalato-κ4O1,O2:O1′,O2′-bis[[4-(2-aminoethyl)-1H-imidazole-κ2N3,N4](azido-κN1)copper(II)], [Cu2(C2O4)(N3)2(C5H9N3)2], (I), and μ-oxalato-κ4O1,O2:O1′,O2′-bis[[4-(2-aminoethyl)-1H-imidazole-κ2N3,N4](dicyanamido-κN1)copper(II)], [Cu2(C2O4)(C2N3)2(C5H9N3)2], (II), are two oxalate-bridged dinuclear copper complexes. Each CuIIion adopts a five-coordinate square-pyramidal coordination sphere where the basal N2O2plane is formed by two O atoms of the oxalate ligand and two N atoms of a bidentate chelating histamine molecule. The apical coordination site in compound (I) is occupied by a monodentate azide anion through one of its terminal N atoms. The apical coordination site in compound (II) is occupied by a monodentate dicyanamide anion through one of its terminal N atoms. The molecules in both structures are centrosymmetric. In the crystals of compounds (I) and (II), the dinuclear complexes are linked through N—H...Xand C—H...X(X= N, O) hydrogen bonds where the donors are provided by the histamine ligand and the acceptor atoms are provided by the azide, dicyanamide, and oxalate ligands. In compound (I), the coordinatively unsaturated copper ions interact with the histamine ligandviaa C—H...Cu interaction. The coordinatively unsaturated copper ions in compound (II) interactviaa weak N...Cu interaction with the dicyanamide ligand of a neighboring molecule. The side chain of the histamine ligand is disordered over three sets of sites in (II).

A switch between two-, three-, and four-stranded coiled coils in GCN4 leucine zipper mutants

Science ◽  
1993 ◽  
Vol 262 (5138) ◽  
pp. 1401-1407 ◽  
Author(s):  
P. Harbury ◽  
T Zhang ◽  
P. Kim ◽  
T Alber
Keyword(s):  
Leucine Zipper ◽  
Coiled Coils

Supramolecular Liquid-Crystalline Side-Chain Polymers Built through a Molecular Recognition Process by Double Hydrogen Bonds

1995 ◽  
Vol 28 (26) ◽  
pp. 8875-8876 ◽  
Author(s):  
Takashi Kato ◽  
Masahisa Nakano ◽  
Tomonori Moteki ◽  
Toshiyuki Uryu ◽  
Seiji Ujiie
Keyword(s):  
Molecular Recognition ◽  
Hydrogen Bonds ◽  
Liquid Crystalline ◽  
Side Chain ◽  
Recognition Process ◽  
Double Hydrogen

scholarly journals Side-chain repacking calculations for predicting structures and stabilities of heterodimeric coiled coils

2001 ◽  
Vol 98 (26) ◽  
pp. 14825-14830 ◽  
Author(s):  
A. E. Keating ◽  
V. N. Malashkevich ◽  
B. Tidor ◽  
P. S. Kim
Keyword(s):  
Coiled Coils ◽  
Side Chain

(3aS,5aR,6R,8aR)-3a-Hydroxy-5a-methyl-6-[(1R,2E,4R)-1,4,5-trimethyl-2-hexen-1-yl]-3a,4,5,5a,6,7,8,8a-octahydro-2H-cyclopenta[e]benzofuran-2-one

2007 ◽  
Vol 63 (11) ◽  
pp. o4196-o4196
Author(s):  
Wen-liang Wang ◽  
Hong-wen Tao ◽  
Wei Sun ◽  
Qian-Qun Gu ◽  
Wei-Ming Zhu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Absolute Configuration ◽  
Title Compound ◽  
Optical Rotation ◽  
Side Chain ◽  
Compound C ◽  
Extended Chain ◽  
Halotolerant Fungus ◽  
The Absolute

The title compound, C21H32O3, also known as dimethylincisterol A3, was isolated from halotolerant fungus THW-18. It is composed of three fused rings and a side chain. In the crystal structure, the molecules interact with each other via O—H...O hydrogen bonds, resulting in an extended chain along the b axis. The absolute configuration was assigned from the measured optical rotation and reference to the literature.

scholarly journals A substrate selected by phage display exhibits enhanced side-chain hydrogen bonding to HIV-1 protease

2018 ◽  
Vol 74 (7) ◽  
pp. 690-694 ◽  
Author(s):  
Ian W. Windsor ◽  
Ronald T. Raines
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Molecular Recognition ◽  
Hydrogen Bonds ◽  
Phage Display ◽  
Directed Evolution ◽  
Side Chain ◽  
Endogenous Substrates ◽  
Hiv 1 ◽  
Additional Hydrogen

Crystal structures of inactive variants of HIV-1 protease bound to peptides have revealed how the enzyme recognizes its endogenous substrates. The best of the known substrates is, however, a nonnatural substrate that was identified by directed evolution. The crystal structure of the complex between this substrate and the D25N variant of the protease is reported at a resolution of 1.1 Å. The structure has several unprecedented features, especially the formation of additional hydrogen bonds between the enzyme and the substrate. This work expands the understanding of molecular recognition by HIV-1 protease and informs the design of new substrates and inhibitors.

scholarly journals 3-Acetyl-1-(3-methylphenyl)thiourea

2012 ◽  
Vol 68 (8) ◽  
pp. o2574-o2574 ◽  
Author(s):  
B. Thimme Gowda ◽  
Sabine Foro ◽  
Sharatha Kumar
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Title Compound ◽  
Side Chain ◽  
Maximum Deviation ◽  
Methyl Groups ◽  
Compound C ◽  
Ring Motif

In the crystal structure of the title compound, C10H12N2OS, the conformation of the two N—H bonds areantito each other. The amide C=O and the C=S are are alsoantito each other. The N—H bond adjacent to the benzene ring issynto them-methyl groups. The dihedral angle between the benzene ring and the side chain [mean plane of atoms C—C(O)N—C—N; maximum deviation 0.029 (2) Å] is 14.30 (7)°. There is an intramolecular N—H...O hydrogen bond generating anS(6) ring motif. In the crystal, the molecules are linkedviaN—H...) hydrogen bonds, forming chains propagating along [001]. The S atom is disordered and was refined using a split model [occupancy ratio 0.56 (4):0.44 (4)].

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