1H, 13C and 199Hg NMR characteristics of new amine-mercuric chloride complexes

Reduction of some N-alkylimines has been achieved with NaBH₄ to give the corresponding secondary amines with high yields (85–95%). These amines were characterized on the bases of their ¹H and ¹³C NMR spectra. The reaction of these amines with mercuric chloride to afford the corresponding complexes was found to occur through a weak dative bond between the nitrogen lone pair of electrons and the mercury atom to form HgCl₂L₂ complexes. The ¹H, ¹³C and ¹⁹⁹Hg NMR chemical shifts have been obtained as well as ¹J(¹³CH) and ²J(¹³CH) coupling constants. Labelling with nitrogen-15 revealed that there is a weak coupling between the nitrogen and the ¹⁹⁹Hg.     

1H, 13C and 15N chemical shift referencing in biomolecular NMR

Summary A considerable degree of variability exists in the way that ¹H, ¹³C and ¹⁵N chemical shifts are reported and referenced for biomolecules. In this article we explore some of the reasons for this situation and propose guidelines for future chemical shift referencing and for conversion from many common ¹H, ¹³C and ¹⁵N chemical shift standards, now used in biomolecular NMR, to those proposed here.Abbreviations TMS tetramethylsilane - TSP 3-(trimethylsilyl)-propionate, sodium salt - DSS 2,2-dimethyl-2-silapentane-5-sulfonate, sodium salt - TFE 2,2,2-trifluoroethanol - DMSO dimethyl sulfoxide     

1H, 13C,and 15N assignments and secondary structure of the FK506 binding protein when bound to ascomycin

The ¹H, ¹³C, and ¹⁵N resonances of FKBP when bound to the immunosuppressant, ascomycin, were assigned using a computer-aided analysis of heteronuclear double and triple resonance three-dimensional nmr spectra of [U-¹⁵N] FKBP/ascomycin and [U-¹⁵N, ¹³C] FKBP/ascomycin. In addition, from a preliminary analysis of two heteronuclear four-dimensional data sets, ³J coupling constants, amide exchange data, and the differences between the C^α and C^β chemical shifts of FKBP to random coil values, the secondary structure of FKBP when bound to ascomycin was determined. The secondary structure of FKBP when bound to ascomycin in solution closely resembled the x-ray structure of the FKBP/FK506 complex but differed in some aspects from the structure of uncomplexed FKBP in solution. © 1993 John Wiley & Sons, Inc.     

1H, 15N and 13C NMR assignments of mouse methionine sulfoxide reductase B2

A recombinant mouse methionine-r-sulfoxide reductase 2 (MsrB2ΔS) isotopically labeled with ¹⁵N and ¹⁵N/¹³C was generated. We report here the ¹H, ¹⁵N, and ¹³C NMR assignments of the reduced form of this protein. An erratum to this article can be found at     

pH-Abhängigkeit der 13C-15N-kopplungskonstanten 15N-hochmarkierter aminosäuren,gewonnen aus algenmassenkulturenpH dependence of 13C-15N coupling constants of highly 15N-enriched amino acid isolated from mass cultivation of algae

The alga Ankistrodesmus braunii was grown with [¹⁵N]nitrate under the optimized conditions of a large-scale mass cultivation. 19.7% of the dried algae were isolated as a mixture of amino acids. The ¹⁵N-labelled amino acids (¹⁵N content up to 98%) were separated by ion exchange chromatography using pyridine acetate gradients. The ¹⁵N content of the analytically pure amino acids was determined by combined gas-liquid chromatography-mass spectrometry of the trifluoroacetylated methylesters and by emission spectroscopy in the ¹⁵N analysator. Using pulse Fourier transform ¹³C nuclear magnetic resonance, the pH dependence of the ¹³C-¹⁵N coupling constants of Asp, Pro, Ser, Glu, Gly, Ala, Val, Ile and Leu was determined in aqueous solutions. Increasing coupling constants were found with pH and decreasing electron density, respectively. The relation of Binsch et al. (Binsch, G., Lambert, J.B., Roberts, B.W. and Roberts, J.D. (1964) J. Am. Chem. Soc. 86, 5564–5570) between the coupling constant and the product of the S-part of the ¹³C and ¹⁵N hybridization $\text{S}{}_{\mathrm{C}}\text{·}\text{S}{}_{\mathrm{N}}\text{= 80 · J (}{}^{13}\text{C}\text{-}{}^{15}\text{X}\text{)}$ fits best in acidic medium. The magnitude of the coupling constants correlates well with the electron densities calculated by Del Re et al. (Del Re, G., Pullman, B. and Yonezawa, T. (1963) Biochim. Biophys. Acta 75, 153–182). The recording of ¹³C nuclear magnetic resonance spectra over the entire pH range revealed no change in the sign of the ¹³C-¹⁵N coupling constants of the amino acids.     

NMR assignments of 1H, 13C and 15N spectra of methionine sulfoxide reductase B1 from Mus musculus

Isotopically labeled, ¹⁵N and ¹⁵N/¹³C forms of recombinant methionine-r-sulfoxide reductase 1 (MsrB1, SelR) from Mus musculus were produced, in which catalytic selenocysteine was replaced with cysteine. We report here the ¹H, ¹⁵N and ¹³C NMR assignment of the reduced form of this mammalian protein.     

1H, 13C, 15N backbone and side-chain resonance assignments of rat angiogenin

Angiogenin is an unusual member of the pancreatic ribonuclease superfamily that induces formation of new blood vessels and is a promising anti-cancer target. Here we report backbone and side chain ¹H, ¹³C, and ¹⁵N resonance assignments for rat angiogenin (residues 24–145), excluding the N-terminal signal peptide. These data allow nuclear magnetic resonance structure and inhibitor-binding studies with the aim of providing angiogenin antagonists as potential therapeutics.     

1H, 13C, and 15N NMR assignments of the actinoporin Sticholysin I

Sticholysin I is an actinoporin, a pore forming toxin, of 176 aminoacids produced by the sea anemone Stichodactyla heliantus. Isotopically labelled ¹³C/¹⁵N recombinant protein was produced in E. coli. Here we report the complete NMR ¹⁵N, ¹³C and ¹H chemical shifts assignments of Stn I at pH 4.0 and 25°C (BMRB No. 15927).     

1H, 15N and 13C assignments of the dimeric C-terminal domain of HIV-1 capsid protein

HIV-1 capsid protein (CA) encloses the viral RNA genome and forms a conical-shaped particle in the mature HIV-1 virion, with orderly capsid assembly and disassembly critically important for viral infectivity. The 231 residue CA is composed of two helical domains, connected by a short linker sequence. In solution, CA exhibits concentration dependent dimerization which is mediated by the C-terminal domain (CTD). Here, we present nearly complete ¹H, ¹⁵N and ¹³C assignments for the 20 kDa homodimeric CA–CTD, a prerequisite for structural characterization of the CA–CTD dimer.     

1H, 15N, 13C resonance assignment of the AlgE6R1 subunit from the Azotobacter vinelandii mannuronan C5-epimerase

Isotopically labelled, ¹³C/¹⁵N from of recombinant subunit of the first R-module from alginate C5-epimerase 6 (AlgE6R1) from Azotobacter vinelandii mannuronan C5-epimerase was produced. We report here the ¹H, ¹⁵N, ¹³C resonance assignment of this subunit from AlgE6 epimerase.     

1H, 13C and 15N resonances of the AlgE62 subunit from Azotobacter vinelandii mannuronan C5-epimerase

The 17.7 kDa R2 module from Azotobacter vinelandii mannronan C5-epimerase AlgE6 has been isotopically labeled (¹³C,¹⁵N) and recombinantly expressed. Here we report the ¹H, ¹³C, ¹⁵N resonance assignment of AlgE6R2.     

1H, 13C, and 15N resonance assignment of photoactive yellow protein

Photoactive yellow protein (PYP) is involved in the negative phototactic response towards blue light of the bacterium Halorhodospira halophila. Here, we report nearly complete backbone and side chain ¹H, ¹³C and ¹⁵N resonance assignments at pH 5.8 and 20 °C of PYP in its electronic ground state.     

1H, 13C and 15N backbone and side-chain chemical shift assignments for oxidized and reduced desulfothioredoxin

Based on sequence homology, desulfothioredoxin (DTrx) from Desulfovibrio vulgaris Hildenborough has been identified as a new member of the thioredoxin superfamily. Desulfothioredoxin (104 amino acids) contains a particular active site consensus sequence, CPHC probably correlated to the anaerobic metabolism of these bacteria. We report the full ¹H, ¹³C and ¹⁵N resonance assignments of the reduced and the oxidized form of desulfothioredoxin (DTrx). 2D and 3D heteronuclear NMR experiments were performed using uniformly ¹⁵N-, ¹³C-labelled DTrx. More than 98% backbone and 96% side-chain ¹H, ¹³C and ¹⁵N resonance assignments were obtained. (BMRB deposits with accession number 16712 and 16713).     

1H, 13C and 15N resonance assignments for Binder of Arl2, BART

We report ¹H, ¹³C and ¹⁵N resonance assignments for Binder of Arl Two (BART), an effector of the small G protein Arl2. The BMRB accession code is 15914.     

1H, 13C,and 15N NMR assignments of a Drosophila Hedgehog autoprocessing domain

The Hedgehog (Hh) signaling pathway plays important roles in embryonic growth and patterning in different organisms. Abnormal activity of the Hh signaling pathway has been associated to cancers, holoprosencephaly and autism spectrum disorders. The backbone and side chain resonance assignments of a Drosophila Hh autoprocessing domain have been determined based on triple-resonance experiments with the [¹³C, ¹⁵N]-labeled and [²H, ¹³C, ¹⁵N])-labeled proteins.     

1H, 13C, and 15N resonance assignment of the TIR domain of human MyD88

Myeloid differentiating factor 88 (MyD88) is one of a critical adaptor molecule in the Toll-like receptor (TLR) signaling pathway. The TIR domain of MyD88 serves as a protein–protein interaction module and interacts with other TIR-containing proteins such as Mal (MyD88 adaptor-like) and Toll-like receptor 4 to form signal initiation complexes. Here we report the ¹⁵N, ¹³C, and ¹H chemical shift assignments of the TIR domain of MyD88. The resonance assignments obtained in this work will contribute to the study of heteromeric TIR–TIR interactions between MyD88 and TIR-containing receptors or adaptors.     

1H, 13C and 15N backbone and side-chain resonance assignments of reduced CcmG from Escherichia coli

CcmG is a periplasmic, membrane-anchored protein widely distributed in a variety of species. In Escherichia coli, the CcmG protein always acts as a weak reductant in the electron transport chain during cytochrome c maturation (Ccm). Here we report ¹H, ¹⁵N and ¹³C backbone and side-chain resonance assignments of the reduced CcmG protein (residues 19–185, renumbered as 1–167) from E. coli. This work lays the essential basis for the further structural and functional analysis of reduced CcmG.     

1H, 13C, and 15N resonance assignments of the N-terminal domain of human Tubulin Binding Cofactor C

Human Tubulin Binding Cofactor C (hTBCC) is a 346 amino acid protein composed of two domains, which is involved in the folding pathway of newly synthesized α and β-tubulins. The 3D structure of the 111-residue hTBCC N-terminal domain of the protein has not yet been determined. As a previous step to that end, here we report the NMR ¹H, ¹⁵N, and ¹³C chemical shift assignments at pH 6.0 and 25°C, based on a uniformly doubly labelled ¹³C/¹⁵N sample of the domain.     

HNHC: a triple resonance experiment for correlating the H2, N1(N3) and C2 resonances in adenine nucleobases of <Superscript>13</Superscript>C-, <Superscript>15</Superscript>N-labeled RNA oligonucleotides

A novel NMR pulse sequence has been developed that correlates the H2 resonances with the C2 and the N1 (N3) resonances in adenine nucleobases of ¹³C, ¹⁵N labeled oligonucleotides. The pulse scheme of the new 3D-HNHC experiment is composed of a ²J-¹⁵N-HSQC and a ¹J-¹³C-HSQC and utilizes large ²J(H2, N1(N3)) and ¹J(H2, C2) couplings. The experiment was applied to a medium-size ¹³C, ¹⁵N-labeled 36mer RNA. It is useful to resolve assignment ambiguities occurring especially in larger RNA molecules due to resonance overlap in the ¹H-dimension. Therefore, the missing link in correlating the imino H3 resonances of the uracils across the AU base pair to the H8 resonances of the adenines via the novel pulse sequence and the TROSY relayed HCCH-COSY (Simon et al. in J Biomol NMR 20:173–176 2001) is provided. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.