NMR studies of transformations of Pt(II) and Pd(II) complexes with amino acids in solution. 1. Glycine complexes

2000 ◽  
Vol 41 (2) ◽  
pp. 243-253 ◽  
Author(s):  
L. F. Krylova ◽  
A. V. Golovin
Keyword(s):  
Amino Acids ◽  
Nmr Studies

Protein environment affects the water–tryptophan binding mode. MD, QM/MM, and NMR studies of engrailed homeodomain mutants

2018 ◽  
Vol 20 (18) ◽  
pp. 12664-12677 ◽  
Author(s):  
Nad'a Špačková ◽  
Zuzana Trošanová ◽  
Filip Šebesta ◽  
Séverine Jansen ◽  
Jaroslav V. Burda ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lone Pair ◽  
Binding Mode ◽  
The Other ◽  
Water Molecules ◽  
Interaction Type ◽  
Nmr Studies ◽  
Engrailed Homeodomain ◽  
The One ◽  
Protein Environment

Water molecules can interact with the π-face of tryptophan either forming an O–H⋯π hydrogen bond or by a lone-pair⋯π interaction. Surrounding amino acids can favor the one or the other interaction type.

NMR Studies of the Reaction of Amino Acids with Aqueous Chlorine

1997 ◽  
Author(s):  
Frank E. Scully, Jr ◽  
Barbara Conyers
Keyword(s):  
Amino Acids ◽  
Aquatic Organisms ◽  
Nondestructive Method ◽  
Resonance Spectroscopy ◽  
Nmr Studies ◽  
Wastewater Disinfection ◽  
Water And Wastewater ◽  
Gas Chromatography Mass Spectroscopy ◽  
The Relationship ◽  
By Products

Over the past 20 years, gas chromatography/mass spectroscopy (GC/MS) has been widely used to identify trace organic environmental contaminants and to study the mechanisms of the formation or transformation of organic compounds either by natural or man-made processes. In the area of water and wastewater disinfection, GC/MS has been highly successful in identifying numerous volatile organic chlorination by-products, some of which may pose undesirable health risks to humans and aquatic organisms at concentrations found in some waters. However, despite a considerable amount of research in this area much of the chemistry continues to be poorly understood. Analysis of trace organics by GC/MS relies on the assumption that the compounds to be analyzed are (1) volatile and (2) thermally stable to GC temperatures as high as 300 °C. Because nuclear magnetic resonance spectroscopy (NMR) is a mild and nondestructive method of analysis, it can reveal reactions that occur in water that cannot be observed by GC/MS. Until recently the reactions of amino acids with two or more equivalents of aqueous chlorine were believed to produce aldehydes and nitriles according to equation (1). LeCloirec and Martin have reported that the formation of nitriles in such situations may come in part from the reaction of monochloramine with aldehydes (equation (2)). Because reaction (2) may affect the distribution of products in reaction (1), it was important to determine the relationship between these two reactions. This chapter will review the applications of NMR we have used in studies of the products formed upon chlorination of amino acids.

Microenvironments of Basic Amino Acids in Amphipathic .alpha.-Helixes Bound to Phospholipid: 13C NMR Studies Using Selectively Labeled Peptides

Biochemistry ◽  
1995 ◽  
Vol 34 (28) ◽  
pp. 9219-9226 ◽  
Author(s):  
Sissel Lund-Katz ◽  
Michael C. Phillips ◽  
Vinod K. Mishra ◽  
Jere P. Segrest ◽  
G. M. Anantharamaiah
Keyword(s):  
Amino Acids ◽  
13C Nmr ◽  
Nmr Studies ◽  
Basic Amino Acids

scholarly journals Syntenin-1 Is a New Component of Tetraspanin-Enriched Microdomains: Mechanisms and Consequences of the Interaction of Syntenin-1 with CD63

2006 ◽  
Vol 26 (20) ◽  
pp. 7707-7718 ◽  
Author(s):  
Nadya Latysheva ◽  
Gairat Muratov ◽  
Sundaresan Rajesh ◽  
Matthew Padgett ◽  
Neil A. Hotchin ◽  
...  
Keyword(s):  
Amino Acids ◽  
Plasma Membrane ◽  
Tyrosine Kinases ◽  
Pdz Domain ◽  
Binding Pocket ◽  
Resonance Spectroscopy ◽  
Nmr Studies ◽  
Transmembrane Receptors ◽  
C Terminus ◽  
Elevated Expression

ABSTRACT Tetraspanins are clustered in specific microdomains (named tetraspanin-enriched microdomains, or TERM) in the plasma membrane and regulate the functions of associated transmembrane receptors, including integrins and receptor tyrosine kinases. We have identified syntenin-1, a PDZ domain-containing protein, as a new component of TERM and show that syntenin-1 specifically interacts with the tetraspanin CD63. Detailed biochemical and heteronuclear magnetic resonance spectroscopy (NMR) studies have demonstrated that the interaction is mediated by the C-terminal cytoplasmic region of the tetraspanin and the PDZ domains of syntenin-1. Upon interaction, NMR chemical shift perturbations were predominantly localized to residues around the binding pocket of PDZ1, indicating a specific mode of recognition of the cytoplasmic tail of CD63. In addition, the C terminus of syntenin-1 has a stabilizing role in the CD63-syntenin-1 association, as deletion of the last 17 amino acids abolished the interaction. The CD63-syntenin-1 complex is abundant on the plasma membrane, and the elevated expression of the wild-type syntenin-1 slows down constitutive internalization of the tetraspanin. Furthermore, internalization of CD63 was completely blocked in cells expressing a syntenin-1 mutant lacking the first 100 amino acids. Previous results have shown that CD63 is internalized via AP-2-dependent mechanisms. Hence, our data indicate that syntenin-1 can counteract the AP-2-dependent internalization and identify this tandem PDZ protein as a new regulator of endocytosis.

scholarly journals Synthesis, Characterization, and Antibacterial Studies of Mixed Ligand Dioxouranium Complexes with 8-Hydroxyquinoline and Some Amino Acids

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Sunil S. Patil ◽  
Ganesh A. Thakur ◽  
Manzoor M. Shaikh
Keyword(s):  
Amino Acids ◽  
Magnetic Susceptibility ◽  
Metal Ion ◽  
Pathogenic Bacteria ◽  
Electronic Absorption Spectra ◽  
Thermal Studies ◽  
Electrical Conductance ◽  
Analysis Data ◽  
Mixed Ligand ◽  
Nmr Studies

Mixed ligand complexes of dioxouranium (VI) of the type [UO2(Q)(L)·2H2O] have been synthesized using 8-hydroxyquinoline (HQ) as a primary ligand and amino acids (HL) such as L-threonine, L-tryptophan, and L-isoleucine as secondary ligands. The metal complexes have been characterized by elemental analysis, electrical conductance, magnetic susceptibility measurements, and spectral and thermal studies. The electrical conductance studies of the complexes indicate their nonelectrolytic nature. Magnetic susceptibility measurements revealed diamagnetic nature of the complexes. Electronic absorption spectra of the complexes show intraligand and charge transfer transitions, respectively. Bonding of the metal ion through N- and O-donor atoms of the ligands is revealed by IR studies, and the chemical environment of the protons is confirmed by NMR studies. The thermal analysis data of the complexes indicate the presence of coordinated water molecules. The agar cup and tube dilution methods have been used to study the antibacterial activity of the complexes against the pathogenic bacteria S. aureus, C. diphtheriae, S. typhi, and E. coli.

1H NMR Studies of Alginate Interactions with Amino Acids

2003 ◽  
Vol 18 (4) ◽  
pp. 283-296 ◽  
Author(s):  
Maria Enrica di Cocco ◽  
Cristiano Bianchetti ◽  
Federica Chiellini
Keyword(s):  
Amino Acids ◽  
1H Nmr ◽  
Nmr Studies

scholarly journals Investigation of exponential RNA amplification by the Qβ replicase complex

2014 ◽  
Vol 70 (a1) ◽  
pp. C1602-C1602
Author(s):  
Heidi Olesen ◽  
Charlotte Knudsen ◽  
Paulina Seweryn ◽  
Ditlev Brodersen ◽  
Zarina Kutlubaeva ◽  
...  
Keyword(s):  
Amino Acids ◽  
Nmr Spectroscopy ◽  
Rna Virus ◽  
Β Subunit ◽  
Rna Amplification ◽  
Nmr Studies ◽  
Basic Amino Acids ◽  
Rna Backbone

Positive-stranded RNA viruses are common among human pathogenic viruses, which often cooperate with host proteins to fulfill essential functions during infection. One function is replication of the viral genome. The Qβ phage is a positive-stranded RNA virus that infects E.coli. The Qβ replicase holo enzyme comprises the phage-encoded RNA-dependent RNA polymerase (β-subunit) and the host-encoded translation elongation factors, EF-Ts and EF-Tu as well as the ribosomal protein S1. The Qβ replicase has an extraordinary ability to exponentially amplify RNA in vivo and in vitro. A prerequisite for this is release of product and template RNA as single strands that can serve as new templates in subsequent rounds of replication. The role of S1 in the Qβ replicase is not clear. Recently, S1 was found to promote release of single-stranded product in Qβ replicase–mediated RNA synthesis. We have undertaken NMR spectroscopy and crystallization trials to improve our understanding of distinct S1 domains in solution as well as the ribosome- and replicase-binding properties of S1. Expression of distinct S1 domains for NMR spectroscopy has been optimized by use of autoinduction and results in high yields of [13C15N]-labelled protein fragments. These have proven very suitable for NMR studies and spectra revealed both ordered and disordered regions in the protein. Studies are ongoing. The structure of the Qβ core complex was recently determined at 2.5Å resolution. Thus, co-crystallization of the Qβ core in complex with S1 domains was undertaken and different crystal forms were obtained. These initial crystals diffracted to 3.2Å resolution and data processing as well as further optimization of the crystals is ongoing. S1 is thought to bind the β-subunit close to a region lined with basic amino acids, which potentially could facilitate interactions with the template RNA backbone and split it from the product strand. We demonstrate that neutralization of these basic amino acids indeed decrease or abolish infectivity of the Qβ phage. However, only one mutation, R503A affects the exponential replication in vitro. Crystallization of the Qβ holo enzyme bound to a truncated legitimate RNA template will be the next step for investigation of the mechanism of exponential RNA amplification by Qβ replicase.

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