Complete proton and carbon-13 assignments of coenzyme B12 through the use of new two-dimensional NMR experiments

Summers, Michael F.; Marzillï, Luigi G.; Bax, Ad

doi:10.1021/ja00275a008

Cited by 786 publications

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“…The heteronuclear 3D TOCSY-jr-HMQC (mixing period of 50 ms) and NOESY-jr-HMQC (mixing time of 100 ms) spectra [16,17] were run consecutively in order to minimize differences in sample conditions. Additional 3D NOESY-jr-HMQC and HMQC-NOESY-jr-HMQC spectra of the next sample of L7/L12 were obtained with mixing time of 180 and 100 ms, respectively.…”

Section: Methodsmentioning

confidence: 99%

Topology of the secondary structure elements of ribosomal protein L7/L12 from E. coli in solution

1996

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Topology of the secondary structure elements of ribosomal protein L7/L12 has been studied. The sequential assignment was obtained for main and side chain resonances. This allows the overall secondary structure to be described. The results of high resolution NMR studies show that dimer of the ribosomal protein L7/L12 from Escheriehia coli has a parallel (head-tohead) orientation of subunits, and N-terminal domain (NTD, residues Serl--Ser33) has no contacts with the C-terminal domain (CTD, residues Lys51-Lysl20). The NMR data for CTD are in line with crystallographic structure. The flexible interdomain (hinge) region (residues Ala34-Glu50) has an unordered structure, the Pro44 forming both cis and trans peptide bonds. Due to the conformational exchange the intensities of the peaks from the NTD are low. The conformation of the NTD, which is responsible for the formation of the L7/L12 dimer, is a-helical hairpin. The NTD dimer forms an antiparallel four-t~-helix bundle.

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Section: Methodsmentioning

confidence: 99%

Topology of the secondary structure elements of ribosomal protein L7/L12 from E. coli in solution

1996

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“…Chemical shifts were set relative to the tetramethylsilane for 'H and to an external standard of I5NH4C1 (2.9 M in 1 M HCl, 30°C, 24.93 ppm relative to NH3). As spectra of similar sensitivity and line width were recorded using heteronuclear multiple-quantum coherence (HMQC) (Summers et al, 1986), heteronuclear single and multiple quantum coherence (HSMQC) (Zuiderveg et al, 1990) or heteronuclear singlequantum coherence (HSQC) (Bax et al, 1990;Clore et al, 1990) experiments, only HMQC spectra are reported throughout. Quadrature detection in t l was achieved by the method of States-Habercorn-Reuben (States et al, 1982).…”

Section: Chlorella Vulgarismentioning

confidence: 99%

¹H‐¹⁵N‐NMR studies of bacteriorhodopsin Halobacterium halobium

Orekhov

Abdulaeva

Musina

et al. 1992

European Journal of Biochemistry

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Series of uniformly and selectively 15N‐labeled bacteriorhodopsins of Halobacterium halobium (strain ET 1001) were obtained and a 1H‐15N‐NMR study was performed in methanol/chloroform (1:1) and 0.1 M NH4CHOO, medium which mimics that in the membrane in vivo. Less than half of the cross‐peaks expected from the amino acid sequence of uniformly 15N‐labeled bacteriorhodopsin were observed, using heteronuclear 1H‐15N coherence spectroscopy. In order to assign the observed cross‐peaks, a selective 15N‐labeling of amino acid residues (Tyr, Phe, Trp, Lys, Gly, Leu, Val or Ile) was carried out and 1H‐15N‐NMR spectra of bacteriorhodopsin and its fragments C1 (residues (72–231), C2 (residues 1–71), B1 (residues 1–155) and BP2 (residues 163–231) were investigated. By this procedure, all observed 1H‐15N cross‐peaks of the entire bacteriorhodopsin were found to belong to the transmembrane segments A, B and G. The cross‐peaks from four (C, D, E and F) helical bundles (79–189 residues) were missed. These results clearly indicate that dynamic processes occur in the four helice bundle. The significance of this, in respect to bacteriorhodopsin functioning, is discussed.

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“…The molecular formula of 1 was established as C 27 H 34 N 2 O 2 by high-resolution FAB-MS. 13 C and 1 H NMR data for 1 are summarized in Table 1. All one-bond 1 H-13 C connectivities were confirmed by the heteronuclear multiple-quantum coherence (HMQC) 4 spectrum. COSY and heteronuclear multiple-bond correlation (HMBC) 5 experiments identified three partial structures as shown in Figure 2.…”

mentioning

confidence: 90%

Dechlororoseophilin: a new cytotoxic metabolite from Streptomyces griseoviridis

2009

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Roseophilin, 1 a cytotoxic pigment produced by Streptomyces griseoviridis 2464-S5, has a unique structure containing two pyrrole and one furan rings as shown in Figure 1. The strain also produces a structurally related tripyrrole antibiotic, prodigiosin R1. 2 Recently, we identified the rph gene cluster for prodigiosin biosynthesis in S. griseoviridis. 3 The rph cluster, however, does not contain genes characteristic of roseophilin biosynthesis, although roseophilin is considered to be biosynthesized partially with the same pathway as prodigiosin R1. We attempted to search the biosynthetic intermediates of roseophilin for further biosynthetic study. Color-guided fractionation of the culture extract resulted in the isolation of a new metabolite, dechlororoseophilin (1, Figure 1). We report herein the fermentation, isolation, structure elucidation and biological activity of 1.The producing organism was cultivated in 500-ml Erlenmeyer flasks containing 100 ml of a medium consisting of glycerol 4.0%, soybean meal 1.5%, molasses 1% and calcium carbonate 0.4% (pH 6.8) on a rotary shaker at 27 1C for 5 days. The fermentation broth (2.0 l) was centrifuged and the mycelium was extracted with acetone. After evaporation, the aqueous concentrate was extracted with ethyl acetate. The extract was applied to a silica gel column, which was washed with chloroform-methanol (10:1) and eluted with chloroform-methanol-29% ammonia water (200:20:1). The eluted pigment was subjected to reversed-phase HPLC (XBridge C 18 , Waters Corporation, Milford, MA, USA) using 88% methanol with 0.2% triethylamine. A pigment fraction was concentrated and dissolved in ethyl acetate. After the solution was washed with 0.1 M hydrochloric acid and water, the organic layer was concentrated to dryness to give a red powder of 1 (8.2 mg). The physico-chemical properties of 1 are summarized as follows: m.p. 81-86 1C; high-resolution FAB-MS m/z 419.2697 (MH + , calcd for C 27 H 35 N 2 O 2 , 419.2701); UV l max (e) 536 nm (142 000) in methanol, 536 nm (143 000) in 0.01 M HCl-methanol, 300 nm (43 400), 485 nm (42 100) in 0.01 M NaOH-methanol; IR (KBr) n max 3450, 2910, 1590, 1290 cm À1 .The molecular formula of 1 was established as C 27 H 34 N 2 O 2 by high-resolution FAB-MS. 13 C and 1 H NMR data for 1 are summarized in Table 1. All one-bond 1 H-13 C connectivities were confirmed by the heteronuclear multiple-quantum coherence (HMQC) 4 spectrum. COSY and heteronuclear multiple-bond correlation (HMBC) 5 experiments identified three partial structures as shown in Figure 2. Three aromatic protons (1-H-3-H) were coupled with each other and an exchangeable proton (1-NH) was coupled with 1-H. A pyrrole moiety was constructed by 1 H-13 C long-range correlations from 1-H to C-2, C-3 and C-4, from 2-H to C-1 and C-4, and from 3-H to C-1 and C-4. NOESY correlations on 1-H, 2-H and 3-H confirmed the structure of a 2-pyrrolyl group and their assignments. 1 H-13 C long-range couplings were observed from 6-H to C-5, C-7 and C-8, and from a methoxy proton (27-H 3 ) to C-7. A...

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Complete proton and carbon-13 assignments of coenzyme B12 through the use of new two-dimensional NMR experiments

Cited by 786 publications

References 0 publications

Topology of the secondary structure elements of ribosomal protein L7/L12 from E. coli in solution

Topology of the secondary structure elements of ribosomal protein L7/L12 from E. coli in solution

¹H‐¹⁵N‐NMR studies of bacteriorhodopsin Halobacterium halobium

Dechlororoseophilin: a new cytotoxic metabolite from Streptomyces griseoviridis

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Complete proton and carbon-13 assignments of coenzyme B12 through the use of new two-dimensional NMR experiments

Cited by 786 publications

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Topology of the secondary structure elements of ribosomal protein L7/L12 from E. coli in solution

Topology of the secondary structure elements of ribosomal protein L7/L12 from E. coli in solution

1H‐15N‐NMR studies of bacteriorhodopsin Halobacterium halobium

Dechlororoseophilin: a new cytotoxic metabolite from Streptomyces griseoviridis

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¹H‐¹⁵N‐NMR studies of bacteriorhodopsin Halobacterium halobium