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1.
K. Chandrasekhar A. Patricia Campbell Mei-Fen Jeng Arne Holmgren H. Jane Dyson 《Journal of biomolecular NMR》1994,4(3):411-432
Summary As a prelude to complete structure calculations of both the oxidized and reduced forms of Escherchia coli thioredoxin (Mr 11 700), we have analyzed the NMR data obtained for the two proteins under identical conditions. The complete aliphatic 13C assignments for both oxidized and reduced thioredoxin are reported. Correlations previously noted between 13C chemical shifts and secondary structure are confirmed in this work, and significant differences are observed in the C and C shifts between cis- and trans-proline, consistent with previous work that identifies this as a simple and unambiguous method of identifying cis-proline residues in proteins. Reduction of the disulfide bond in the active-site Cys32-Gly-Pro-Cys35 sequence causes changes in the 1H, 15N and 13C chemical shifts of residues close to the active site, some of them quite far distant in the amino acid sequence. Coupling constants, both backbone and side chain, show some differences between the two proteins, and the NOE connectivities and chemical shifts are consistent with small changes in the positions of several side chains, including the two tryptophan rings (Trp28 and Trp31). These results show that, consistent with the biochemical behavior of thioredoxin, there are minimal differences in backbone configuration between the oxidized and reduced forms of the protein. 相似文献
2.
Summary NMR View is a computer program designed for the visualization and analysis of NMR data. It allows the user to interact with a practically unlimited number of 2D, 3D and 4D NMR data files. Any number of spectral windows can be displayed on the screen in any size and location. Automatic peak picking and facilitated peak analysis features are included to aid in the assignment of complex NMR spectra. NMR View provides structure analysis features and data transfer to and from structure generation programs, allowing for a tight coupling between spectral analysis and structure generation. Visual correlation between structures and spectra can be done with the Molecular Data Viewer, a molecular graphics program with bidirectional communication to NMR View. The user interface can be customized and a command language is provided to allow for the automation of various tasks.Inquiries concerning the availability of NMR View and the Molecular Data Viewer should be sent via email to johnsonb@merck.com or to Bruce A. Johnson, Merck Research Laboratories, RY80Y-103, P.O. Box 2000, Rahway, NJ 07065, U.S.A. 相似文献
3.
Summary A 3D triple resonance experiment has been designed to provide intraresidual and sequential correlations between amide nitrogens and -carbons in uniformly 13C15N-labeled proteins. In-phase 13C magnetization is transferred to the aliphatic side-chain protons via the side-chain carbons using a CC-TOCSY mixing sequence. Thus, the experiment alleviates the resonance assignment process by providing information about the amino acid type as well as establishing sequential connectivities. Leaving the carbonyl spins untouched throughout the transfer from 13C to 1H leads to E.COSY-type cross peaks, from which the 3JH
co coupling constants can be evaluated. The pulse sequence is applied to oxidized Desulfovibrio vulgaris flavodoxin. 相似文献
4.
中国优质水果资源的分布与适宜生态环境 总被引:3,自引:0,他引:3
根据农业部在80年代两次组织评选出的全国189个优质水果产地的生态环境资料,用微型电子计算机系统建立数据库,统计分析柑桔、苹果和梨优质产品的构成比例、产区分布地域及其适宜的环境指标和主栽品种的生态适应性,为果树良种区域化栽培与选育提供依据。 相似文献
5.
Sjaak Peelen Sybren S. Wijmenga Paul J. A. Erbel Robert L. Robson Robert R. Eady Jacques Vervoort 《Journal of biomolecular NMR》1996,7(4):315-330
Summary The 1H, 15N and 13C backbone and 1H and 13C beta resonance assignments of the long-chain flavodoxin from Azotobacter chroococcum (the 20-kDa nifF product, flavodoxin-2) in its oxidized form were made at pH 6.5 and 30°C using heteronuclear multidimensional NMR spectroscopy. Analysis of the NOE connectivities, together with amide exchange rates, 3JHnH coupling constants and secondary chemical shifts, provided extensive solution secondary structure information. The secondary structure consists of a five-stranded parallel -sheet and five -helices. One of the outer regions of the -sheet shows no regular extended conformation, whereas the outer strand 4/6 is interrupted by a loop, which is typically observed in long-chain flavodoxins. Two of the five -helices are nonregular at the N-terminus of the helix. Loop regions close to the FMN are identified. Negatively charged amino acid residues are found to be mainly clustered around the FMN, whereas a cluster of positively charged residues is located in one of the -helices. Titration of the flavodoxin with the Fe protein of the A. chroococcum nitrogenase enzyme complex revealed that residues Asn11, Ser68 and Asn72 are involved in complex formation between the flavodoxin and Fe protein. The interaction between the flavodoxin and the Fe protein is influenced by MgADP and is of electrostatic nature.Abbreviations SQ
semiquinone
- FMN
riboflavin 5-monophosphate; nif, nitrogen fixation
- TSP
3-(trimethylsilyl)propionate sodium salt
- DSS
2,2-dimethyl-2-silapentane-5-sulfonate sodium salt
Supplementary Material is available on request, comprising a Materials and Methods section for the expression and purification of the A. chroococcum flavodoxin, a Table S1 containing the parameters of the titration of A. chroococcum flavodoxin with the Fe protein, and a Table S2 containing the 15N, HN, 13C, 1H, 13C, 1H and 13CO chemical shifts.To whom correspondence should be addressed. 相似文献
6.
Yu-Sen Wang Anne F. Frederick Mary M. Senior Barbara A. Lyons Stuart Black Paul Kirschmeier Louise M. Perkins Oswald Wilson 《Journal of biomolecular NMR》1996,7(2):89-98
Summary The growth factor receptor-bound protein-2 (Grb2) is an adaptor protein that mediates signal transduction pathways. Chemical shift assignments were obtained for the SH2 domain of Grb2 by heteronuclear NMR spectroscopy, employing the uniformly 13C-/15N-enriched protein as well as the protein containing selectively 15N-enriched amino acids. Using the Chemical Shift Index (CSI) method, the chemical shift indices of four nuclei, 1H, 13C, 13C and 13CO, were used to derive the secondary structure of the protein. Nuclear Overhauser enhancements (NOEs) were then employed to confirm the secondary structure. The CSI results were compared to the secondary structural elements predicted for the Grb2 SH2 domain from a sequence alignment [Lee et al. (1994) Structure, 2, 423–438]. The core structure of the SH2 domain contains an antiparallel -sheet and two -helices. In general, the secondary structural elements determined from the CSI method agree well with those predicted from the sequence alignment.Abbreviations crk
viral p47gag-crk
- EGF
epidermal growth factor
- GAP
GTPase-activating protein
- PI3K
phosphatidylinositol-3-kinase
- PLC-
phospholipase-C-, shc, src homologous and collagen
- src
sarcoma family of nonreceptor tyrosine kinase 相似文献
7.
Mark G. Hinds Till Maurer Jian-Guo Zhang Nicos A. Nicola and Raymond S. Norton 《Journal of biomolecular NMR》1997,9(2):113-126
The chemical shift assignments and secondary structure of a murine–human chimera,MH35, of leukaemia inhibitory factor (LIF), a 180-residue protein of molecular mass 20 kDa,have been determined from multidimensional heteronuclear NMR spectra acquired on auniformly 13C,15N-labelled sample. Secondary structure elements were defined on the basisof chemical shifts, NH-CH coupling constants, medium-range NOEs and the location ofslowly exchanging amide protons. The protein contains four -helices, the relativeorientations of which were determined on the basis of long-range, interhelical NOEs. The fourhelices are arranged in an up-up-down-down orientation, as found in other four-helical bundlecytokines. The overall topology of MH35-LIF is similar to that of the X-ray crystallographicstructure for murine LIF [Robinson et al. (1994) Cell, 77, 1101–1116]. Differencesbetween the X-ray structure and the solution structure are evident in the N-terminal tail, wherethe solution structure has a trans-Pro17 compared with the cis-Pro17 found in the crystalstructure and the small antiparallel -sheet encompassing residues in the N-terminus andCD loop in the crystal structure is less stable. 相似文献
8.
9.
Maurizio Pellecchia Gerhard Wider Hideo Iwai Kurt Wüthrich 《Journal of biomolecular NMR》1997,10(2):193-197
A novel 2D NMR experiment, 2D HE(NE)HGHH, is presented for the assignment ofarginine side chain 1H and 15N resonances inuniformly 15N-labeled proteins. Correlations between1H, 1Hand 1H are established on the basis of3J(15N,1H) heteronuclear scalarcoupling constants, and sequence-specific assignments are obtained by overlapof these fragments with 1H chemical shiftsobtained by assignment procedures starting from the polypeptide backbone.Since guanidino protons exchange quite rapidly with the bulk water, the 2DHE(NE)HGHH pulse scheme has been optimized to avoid saturation and dephasingof the water magnetization during the course of the experiment. As anillustration, arginine side chain assignments are presented for two uniformly15N-labeled proteins of 7 and 23 kDa molecular weight. 相似文献
10.
Complete 1H, 13C, and 15N NMR resonance assignments and secondary structure of human glutaredoxin in the fully reduced form.
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C. Sun A. Holmgren J. H. Bushweller 《Protein science : a publication of the Protein Society》1997,6(2):383-390
Human glutaredoxin is a member of the glutaredoxin family, which is characterized by a glutathione binding site and a redox-active dithiol/disulfide in the active site. Unlike Escherichia coli glutaredoxin-1, this protein has additional cysteine residues that have been suggested to play a regulatory role in its activity. Human glutaredoxin (106 amino acid residues, M(r) = 12,000) has been purified from a pET expression vector with both uniform 15N labeling and 13C/15N double labeling. The combination of three-dimensional 15N-edited TOCSY, 15N-edited NOESY, HNCA, HN(CO)CA, and gradient sensitivity-enhanced HNCACB and HNCO spectra were used to obtain sequential assignments for residues 2-106 of the protein. The gradient-enhanced version of the HCCH-TOCSY pulse sequence and HCCH-COSY were used to obtain side chain 1H and 13C assignments. The secondary structural elements in the reduced protein were identified based on NOE information, amide proton exchange data, and chemical shift index data. Human glutaredoxin contains five helices extending approximately from residues 4-10, 24-36, 53-64, 83-92, and 94-104. The secondary structure also shows four beta-strands comprised of residues 15-19, 43-48, 71-75, 78-80, which form a beta-sheet almost identical to that found in E. coli glutaredoxin-1. Complete 1H, 13C, and 15N assignments and the secondary structure of fully reduced human glutaredoxin are presented. Comparison to the structures of other glutaredoxins is presented and differences in the secondary structure elements are discussed. 相似文献