solidstate nmr spectroscopy on complex biomolecules

... a,b-anor- meric configuration. However, because of the complexity of overlapping signals of the same monosaccharide residues in a very similar chemical environment, it is difficult for NMR alone to assign ... [17], one trifucosylated [23], one tetrafucosyl- ated [24], and one pentafucosylated [24] oligosaccharides. Acidic structures described include one monosialyl-mono- fucosylated [25], two monosialyl-difucosylated ... gel-filtration and ion-exchange columns with distilled water. The partially resolved octasaccharide to undeca- saccharide fractions were further fractionated by normal- phase HPLC on a preparative Separon...

Ngày tải lên: 19/02/2014, 12:20

... 0.5%. 1 H nuclear magnetic relaxation dispersion (NMRD) pro- files were recorded at variable concentration of myristate by measuring water proton longitudinal relaxation rates (R 1 obs ) at magnetic ... con- centration of the paramagnetic metal ion, and T 1M is the longitudinal relaxation time of localized water protons [20,36]. Relaxivity of Mn(III)heme–HSA solutions at 25.0 ° Cas a function ... 46724683 ê 2005 FEBS 4681 Contributions to relaxation differ, depending on the conformational state of HSA and on the occupancy of the myristate binding sites. The relaxation rate change is highest...

Ngày tải lên: 20/02/2014, 02:22

... experimental conditions, d espite a r elaxation delay of 4.3 s and a satu ration time of 3 s. Nevertheless, saturation transfer to the N-methyl groups was not observed under these conditions. A satura- tion ... legionaminic acid was 1 : 1 in long-chain and 1 : 2 in middle-chain PS NH 4 OH/HF , respectively. Based on the rela- tive intensities of the proton signals it was concluded that only one legionaminic ... exchange could be observed under the conditions applied. From these data it is conclud ed that under certain conditions it is possible to observe the interconversion of the cis and trans N-methyl...

Ngày tải lên: 08/03/2014, 10:20

... (1991) Assignments of backbone 1 H, 13 C, and 15 N resonances and secon dary structure of ribonuclease H from Escherichia coli by heteronuclear three-d imensional NMR spec- troscopy. Biochemistry ... expression systems based on Escheri chia coli extracts [2,10,15,16]. At these yields, protein concentrations are sufficiently high t o allow the recording of NMR spectra without further concentration ... gene, using a combination of ligation and recursive overlap extension of complementary synthetic oligonucleotides as described above. Oligonucleotides used for the construction of the s-CYPA are...

Ngày tải lên: 16/03/2014, 18:20

... typical crystallization conditions comparing the E-andthe Z-configurations are demonstrated in Fig. 3. Despite the identical crystallization conditions, only the E-configuration crystallized (Fig. ... fraction (Fig. 1), only the two naturally occurring PEC-linker complexes are present, confirming the brief dissociation and separation conditions [4]. The second important preparation step was that ... Z-and E-configurations of one chromopeptide with an excellent solubility and stability were investigated by 1D NMR spectroscopy. The information presented here are mainly focused on the preparations,...

Ngày tải lên: 17/03/2014, 10:20

... transition under conditions of slow exchange on the chemical-shift timescale, the dissociation constant, K d , is given by K d ẳẵPẵL=ẵPL Here, [P], [L] and [PL] are the respective concentrations of ... exchange regime. Thus, the configuration at the hemiacetal carbon of galactose may affect the dissociation constants. By contrast, because chemical-shift changes upon the addition of sugars at subdomain ... pulses for saturation with 1 ms intervals and a total saturation time of  2 s. On- res- onance irradiation of the protein was conducted at a chemi- cal shift of –0.4 p.p.m. and off-resonance at a chemical shift...

Ngày tải lên: 23/03/2014, 04:21

... NTX-1 were confirmed by electron spray ionization/mass spectro- metry (ESI-MS). NMR spectroscopy NTX-1 was dissolved in D 2 O/H 2 O (10 : 90, v/v) pH 3.2 or 99.9% (v/v) D 2 O to the final concentration ... flexibility [37]. On the other hand, the substitution o f S er in other long neurotoxins with G ly33 in NTX-1 (Fig. 1) at the tip portion of loop II makes this region conformationally more variable. Binding ... possible explan- ation for the lower dissociation constants of long neuro- toxins from nicotinic acetylcholine receptor c ompared to short ones. Fig. 6. Comparison of NTX-1 NMR and 1NTN X-ray...

Ngày tải lên: 23/03/2014, 13:20

... expression of downstream genes, as appropriate. The expected con- sumption of phenylacetate was confirmed by HPLC of the culture fluid using online liquid-scintillation counting for detection (data ... strains grew on succinate, but none grew on adipate. Transformation of labeled phenylacetate into labeled products by the mutants Mutant cell suspensions were incubated in buffer contain- ing ... carbon atoms (122.1, 123.1, 126.5 and 129.3 p.p.m.; Table 1); they were all correlated to directly attached protons as shown by 2D HMQC spectroscopy (Fig. 4). Carbon connectivities established on...

Ngày tải lên: 23/03/2014, 18:20

... deviations of bond lengths, bond angles and dihedral angles from ideality, unfa- vourable sidechain rotamers, and bad nonbonded interactions. molprobity additionally offers all-atom contact analysis ... ‘resolution’ of NMR- derived protein structures. Assessment criterion Very high resolution High resolution Medium resolution Low resolution Restraints per residue a > 18 14–18 10–15 < 10 Backbone ... macromolecular NMR spectroscopy, including basic interpretation of commonly encoun- tered NMR spectra. We then outline the process by Keywords HSQC; nuclear magnetic resonance (NMR) spectroscopy; ...

Ngày tải lên: 29/03/2014, 00:20

... on the existence of motions on the ps to ns timescale, whereas R 2 additionally depends on slower motions on the ls to ms timescale. These data can be analysed [41–43] to separate contributions ... VTS1p–RNA interac- tion is driven by an increase in conformational entropy. Slower motions (ls-ms) As noted above, R 2 relaxation rates can provide infor- mation on slower internal motions in proteins. Related, ... and such motion can occur on timescales ranging from pico- seconds to seconds or more. Fast motions (ps–ns) These motions are accessible through the measurement of the relaxation rate constants for...

Ngày tải lên: 29/03/2014, 00:20

... [3], the active conformation of EM2 should be taken into con- sideration on the basis of not only the conformational difference in the backbone chain but also the overall conformation, including ... to C-terminal amidation. Solution conformation by NMR spectroscopy and simulated annealing calculation The conformational features of EM2 and EM2OH, obtained by the present NMR measurements and molecular ... docking models were constructed for the open conformers and subjected to energy evaluation for reasonable configur- ation and translation exploration using the Docking module of insight discover. Consequently,...

Ngày tải lên: 30/03/2014, 20:20

... function is unknown, it is dependent on an interaction with the nonsecreted TTSS chaperone LcrH [12,13]. This interaction is responsible for the presecretory stabilization and efficient secretion ... determination of a TTSS chaperone/ effector protein complex from Salmonella spp., it is likely that at least one function of chaperones is to maintain their cognate partner in an elongated unfolded ... application to proton correlation spectroscopy. J. Magn. Reson. 53, 521–528. 25. Jeener, J., Meier, B.H., Bachmann, P. & Ernst, R.R. (1979) Investigation of exchange processes by two-dimensional NMR spectroscopy. ...

Ngày tải lên: 31/03/2014, 21:21

Ngày tải lên: 04/06/2014, 15:22

Ngày tải lên: 21/06/2014, 05:20

Ngày tải lên: 22/06/2014, 18:20