Cysteine 397 plays important roles in the folding of the neuron-restricted silencer factor/RE1-silencing transcription factor.

The neuron-restrictive silencer factor/RE1-silencing transcription factor (NRSF/REST) is regarded as not only a key transcriptional repressor but also an activator in neuron gene expression by specifically interacting with neuron-restrictive silencer element (NRSE/RE1) dsDNA and small NRSE/RE1 dsRNA, respectively. But its exact mechanism remains unclear. One major problem is that it is hard to obtain its functional multiple zinc finger (ZnF) domains in a large quantity for further structural studies.

Solution structure of all parallel G-quadruplex formed by the oncogene RET promoter sequence.

RET protein functions as a receptor-type tyrosine kinase and has been found to be aberrantly expressed in a wide range of human diseases. A highly GC-rich region upstream of the promoter plays an important role in the transcriptional regulation of RET. Here, we report the NMR solution structure of the major intramolecular G-quadruplex formed on the G-rich strand of this region in K(+) solution.

Solution structure of BmKalphaTx11, a toxin from the venom of the Chinese scorpion Buthus martensii Karsch.

The solution structure of BmKalphaTx11 presented by this paper is distinctive from any other structures of wide-type scorpion alpha-toxins reported so far, for its trans-9,10 peptide bond conformation is accompanied by 'protruding' topology of the 'NC-domain'. The orientation of the C-tail of BmKalphaTx11 is obviously different from that of classical alpha-toxins (e.g.

Solution structure of BmKalphaIT01, an alpha-insect toxin from the venom of the Chinese scorpion Buthus martensii Karsch.

The solution structure of an alpha-insect toxin from Buthus martensii Karsch, BmKalphaIT01, has been determined by two-dimensional NMR spectroscopy and molecular modeling techniques. Combining the sequence homology comparison and toxicity bioassays, BmKalphaIT01 has been suggested to be a natural mutant of alpha-insect toxins and so can serve as a tool to study the relationship of structure-function among this group of toxins. The overall structure of BmKalphaIT01 shares a common core structure consisting of an alpha-helix packed against a three-stranded antiparallel beta-sheet, which exhibits distinctive local conformations within the loops connecting these secondary structure elements.

Over-expression and refolding of isotopically labeled recombinant catalytic domain of human macrophage elastase (MMP-12) for NMR studies.

Human macrophage elastase (MMP-12) plays an important role in inflammatory processes and is involved in a number of physiological or pathological situations, such as conversion of plasminogen into angiostatin, allergic airway inflammation, vascular remodeling or alteration, as well as emphysema, and has been justified as a novel drug target. Here, we report the over-expression in Escherichia coil, purification and refolding of MMP-12 catalytic domain for NMR studies. The primary sequence of expressed protein was identified by means of MALDI-TOF MS, and was confirmed by the MALDI-TOF MS data of trypsin-digested peptides.

Interaction sites between the Slo1 pore and the NH2 terminus of the beta2 subunit, probed with a three-residue sensor.

Calcium- and voltage-gated (BK) K(+) channels encoded by Slo1 play an essential role in nervous systems. Although it shares many common features with voltage-dependent K(V) channels, the BK channel exhibits differences in gating and inactivation. Using a mutant in which FWI replaces three residues (FIW) in the NH(2) terminus of wild-type beta2-subunits, in conjunction with alanine-scanning mutagenesis of the Slo1 S6 segment, we identify that the NH(2) terminus of beta2-subunits interacts with the residues near the cytosolic superficial mouth of BK channels during inactivation.

NMR solution structure of BmK-betaIT, an excitatory scorpion beta-toxin without a 'hot spot' at the relevant position.

BmK-betaIT (previously named as Bm32-VI in the literature), an excitatory scorpion beta-toxin, is purified from the venom of the Chinese scorpion Buthus martensii Karsch. It features a primary sequence typical of the excitatory anti-insect toxins: two contiguous Cys residues (Cys37-Cys38) and a shifted location of the fourth disulfide bridges (Cys38-Cys64), and demonstrates bioactivity characteristic of the excitatory beta-toxins. However, it is noteworthy that BmK-betaIT is not conserved with a glutamate residue at the preceding position of the third Cys residue, and is the first example having a non-glutamate residue at the relevant position in the excitatory scorpion beta-toxin subfamily.

Over-expression and purification of isotopically labeled recombinant ligand-binding domain of orphan nuclear receptor human B1-binding factor/human liver receptor homologue 1 for NMR studies.

The human hepatitis B virus enhancer II B1 binding factor (hB1F), which regulates the expression of hepatitis B virus genes, is identified as a nuclear receptor. It regulates several liver-specific genes and plays an important role in the bile acid biosynthesis pathway. A significantly optimized protocol has been worked out to prepare 15N and/or 13C-labeled hB1F ligand-binding domain in minimal medium with high yields for NMR studies.

Solution structure of BmP08, a novel short-chain scorpion toxin from Buthus martensi Karsch.

A novel short-chain scorpion toxin BmP08 was purified from the venom of the Chinese scorpion Buthus martensi Karsch by a combination of gel-filtration, ion exchange, and reversed-phase chromatography. The primary sequence of BmP08 was determined using the tandem MS/MS technique and Edman degradation, as well as results of NMR sequential assignments. It is composed of 31 amino acid residues including six cysteine residues and shares less than 25% sequence identity with the known alpha-KTx toxins.

[Studies on chemical constituents in root of Paeonia sinjiangensis].

Objective: To study the chemical constituents of the root of Paeonia sinjiangensis.

Method: The constituents were isolated by silica column chromatography, and their structures were identified on the basis of spectral analysis and their physical-chemical constants.

Result: Five compounds, paeoniflorin( I ), albiflorin (II), lactiflorin(III), daucosterol(IV), sucrose (V), were obtained.

Serratane-type triterpenoids from Huperzia serrata.

Sixteen serratane-type triterpenoids including three new compounds, 14beta,15beta-epoxyserratan-3beta,21beta,29-triol (1), serrat-14-en-3beta,21beta,29-triol (2) and serrat-14-en-3alpha,21beta,24,29-tetraol (3), were isolated from the whole plant of Huperzia serrata (Thunb) Trev. The structures of these new compounds (1-3) were elucidated on the basis of spectral analysis.

Miyoshianines A and B, two new lycopodium alkaloids from Huperzia miyoshiana.

Two new Lycopodium alkaloids, miyoshianines A and B, together with five known alkaloids, lycopodine, lycodoline, 12-epilycodoline, clavolonine, and flabelliformine, were isolated from Huperzia miyoshiana (Makino) Ching (Huperziaceae). Their structures were determined by means of spectroscopic techniques.