$\alpha$$_1$-arantitrypsin, a member of the serpin (serine protease inhibitor) family, undergoes a large structural rearrangement upon the cleavage and insertion of the reactive site loop. This conformational change is driven by the metastability of the native serpin structures and has an important role in the regulation of the inhibitory-serpin function. (omitted)

In sino-atrial node cells which act as the normal pacemaker of the heart, K conductance in resting state is minimal due to the absence of inward rectifier K channels K conductance only increases when the membrane is depolarized by the activation of the delayed rectifier K current I$\_$k/. In the present study, we investigated the gating mechanism of$\_$k/ using the whole cell patch clamp technique in isolated single sinoatrial cells of the rabbit. (omitted)

Gap junction channels were reconstituted into unilamellar liposomes using immunoaffinity purified connexin 32 gap junction protein from rat liver. Vesicles containing open channels and close channels were separated by means of iso-osmolar sucros density gradient sedimentation. The open channels formed in lipid vesicles were permeable to a fluorescent dye molecule, lucifer yellow of which the hydrodynamic size is similar to pore size of gap junctions in vivo. (omitted)

A new trend that emerges at the turn of the century is the physical approach to biological phenomena. It is expected that biology provides novel materials for condensed matter physics and, most importantly, a revolutionary paradigm for physics at large. On the other hand, physics, if properly extended, is expected to provide systematic and quantitative understanding of biological phenomena, and multitude of biotechnological applications. (omitted)

The regulatory role of A$\_$2A/ adenosine receptors on the P purinoceptor-mediated calcium signaling was investigated in rat pheochromocytoma (PC 12) cells. When PC 12 cells were treated with 2-p-(2-carboxyethyl) phenethylamino- 5' - N -ethylcarboxamido-adenosine (CGS21680), a specific agonist of the A$\_$2A/ adenosine receptor, extracellular ATP-evoked [Ca$\^$2+/]$\_$I/ rise was inhibited by -20%. (omitted)

The immunosuppressive and cell cycle arrest agent rapamycin works by binding together two proteins: the FK506 binding protein (FKBP12) and the FKBP-rapamycin associated protein (FRAP). A 2.7 $\AA$ resolution crystal structure of the triple complex of human FK506 binding protein (FKBP12), rapamycin, and FKBP12-rapamycin binding domain (FRB) of FRAP, reveals two proteins bound together through rapamycin' s ability to simultaneously occupy two different hydrophobic binding pockets. (omitted)

High-resolution solution conformation of a novel conotoxin, [Pro 7,13] $\alpha$A-conotoxin $P_{IVA}$, GCCGSYPNAACHPCSCKDROSYCGQ-N $H_2$, has been determined by two-dimensional $^1$H nmr methods in combination with distance geometry calculation to rmsd values of 0.90 $\AA$ and 1.16 $\AA$ for the backbone and heavy atoms, respectively. Total of 324 NOE-derived interproton distance restraints including 33 long-range NOE restraints a well as 11 $\Phi$ and 7 $\chi$$^1$ torsion angle restraints were used for computation of structures. (omitted)d)

The three-dimensional structure of the carboxyl-terminal domain of the E.coli RNA polymerase $\alpha$ subunit, which is regarded as the contact site for transcription activator proteins and the promoter UP element, was determined by NMR spectroscopy. Its compact structure of four helices and two long arms enclosing its hydrophobic core shows a folding topology distinct from those of other DNA-binding proteins. (omitted)

Aggregation of human $\alpha$$_1$-antitrypsin ($\alpha$$_1$-AT) during folding occurs both in vitro and in vivo. In vivo aggregates of mutant $\alpha$$_1$-AT such as $M_{malton}$ (Phe52 deleted) and Z (Glu342 longrightarrowLys) variants have pathological consequences. In order to analyze the process of $\alpha$$_1$-AT aggregation in detail, the folding-unfolding kinetics of $\alpha$$_1$-AT was examined by monitoring intrinsic Trp fluorescence and ANS binding. (omitted)

The metastable native state of proteins plays an important role in regulating biological functions. The native strain of serpins (serine protease inhibitors) are considered to be crucial for the inhibitory function. Several thermostable mutations of human $\alpha$$_1$-antitrypsin, a prototype inhibitory serpin, were identified in a systematic search targeted at the hydrophobic core of the molecule [Nature structural biology, vol. 3, no. 6, 497-500(1996)]. (omitted)

In order to investigate the conformational preferences to elicit the tastes, conformational free energy calculations using the empirical potential ECEPP/3 and the hydration shell model were carried out on the L-aspartyl dipeptide methyl esters, L-$\^$+/HAsp$\^$-/-D-Xaa-OMe, in the unhydrated state, where Xaa includes sweet (Ala, Abu, Ser, Thr, Val, and lle), bitter (Phe, Trp, and Leu), and tasteless (Tyr and Met) residues. (omitted)

Investigation of the structure of the gangliosides has proven to be very important in the understanding of their biological roles such as regulation of differentiation and growth of cells. Unexchanged hydroxyl protons and amide protons in ganglioside are protrude farther from the carbon backbone than the C-linked protons and provides nOe contacts with other protons which can provide additional distance constraints in structural determination. (omitted)

Annexin I is a member of the annexin family of calcium dependent phospholipid binding proteins and has anti-inflammatory activity by inhibiting phospholipase A$_2$ (PLA$_2$). Recent X-ray crystallographic study of annexin I identified six Ca$\^$2+/ binding sites, which was different types (type II, III) from the well-known EF-hand motif (type I). (omitted)

Bacteriophage T4 endonuclease V initiates the repair of ultraviolet (UV)-induced pyrimidine dimer photoproducts in duplex DNA. The mechanism of DNA strand cleavage involves four sequential steps: linear diffusion along dsDNA, pyrimidine dimer-specific binding, pyrimidine dimer-DNA glycosylase activity, and AP lyase activity. (omitted)

Cyclic AMP receptor protein (CRP) from E. Coli plays a key role in regulation of the expression of more than 20 genes of the bacterium. CRP binds in the presence of cAMP to a specific target site near the promoter of each gene under its regulation. CRP is a dimer (Mr～47,000) of two identical subunits. There are two binding domains in the CRP monomer, one for the binding of the cAMP and the other for the binding of specific DNA sequences. (omitted)

Crystals of a bacterial glutathione S-transferase(pGST) from pseudomonas sp. DJ 77 have been grown by hanging drop method of vapour diffusion from ammonium sulfate solution. The low concentration of polyethylene glycol 400 as additive were found to be essential for the reproducible growth of large single crystal of pGST. (omitted)

The hyperthermostable protein, rubredoxin from Pyrococcus furiosus is 53-residue protein with a three-stranded anti-parallel $\beta$-sheet and several loops. To investigate the effect of changes of electrostatic and hydrophobic interactions on the structure and dynamic property of P. furiosus rubredoxin, molecular dynamics simulations in water were performed on three mesophilic rubredoxins, P, furiosus rubresoxin, and 5 mutants of P. furiosus rubredoxin. (omitted)

In order to establish the structural requirements for designing new ${\beta}$-lactam antibiotics it is necessary to build the molecular model of a penicillin binding protein. D-alanyl-D-alanine carboxypeptidase/transpeptidase (DD-peptidase) is a good model for PBPs. The X -ray crystallographic structure of DD-peptidase has been reported at the 1.6${\AA}$ resolution. (omitted)

A working molecular model of the angiotensin II type 1 receptor is built based on the seven transmembrane helix structure of the recently refined bacteriorhodopsin atomic coordinates. A multiple copy simultaneous search (MCSS) method is used to search the pharmacophore of angiotensin on the surface of the receptor. Multiple copies of amino acid fragments and organic functional groups are scattered around the possible binding site and the time dependent. (omitted)

SecA protein of E. coli is essential for the translocation of various precursor proteins across the plasma membrane. Along with it, SecA protein interacts with precursor proteins, SecY/E, SecB and is an ATPase which has multiple ATP binding sites. There is little known about the regulation mechanism of the protein translocation machinery. (omitted)

A mature mutant ribose binding protein (RBP) of Escherichia coli was obtained by site-directed mutagenesis, replacing Thr-3 in the N-domain of wild-type mature RBP (WT -mRBP) with a Trp residue (N- Trp-mRBP). The equilibrium unfolding properties and the refolding kinetics of this protein were monitored by fluorescence and circular dichroism (CD). (omitted)

The methionine-rich segments of the Fifty four homologue (Ffh) protein of Escherichia coli and its eukaryotic counterpart SRP54 are thought to bind signal sequences of secretory proteins. The structure of a chemically synthesized 25-residue-long peptide corresponding to one of the proposed methionine rich amphiphilic helices of Ffh was determined in water and in aqueous trifluroethanol (TFE) solution using CD ard NMR. (omitted)

SecA protein which has a pivotal role in the preprotein cranslocation across the inner membrane of Escherichia coli is a water-soluble protein with an unusual property of penetrating the membrane readily. An interesting and important question is what structural characteristics of SecA enables its ready penetration of lipid bilayer. The conformational properties of SecA in solution at 3$0^{\circ}C$, pH 7.5 were observed by hydrogen-tritium (HT) exchange, and denaturant-induced denaturation/renaturation and thermal unfolding. (omitted)

NMR studies on the structure of the luteinizing hormone releasing hormone (LHRH) in aqueous buffer and trifluoroethanol (TFE)/aqueous buffer (1:1, v/v) solution were performed. The NMR data under these conditions suggested a unique conformation which includes a ${\beta}$-1 turn of the Tyr5-Arg8 segment and an unusual turn of Ser4-Gly6 segment staggered with the ${\beta}$-I turn. (omitted)

The structure of an antimicrobial peptide buforin II has been studied by $^1$H NMR and CD spectroscopy. Buforin II is flexible and random structure in H$_2$O but the parts of buforin II become helical structure in trifluoroethanol (TFE)/H$_2$O (1:1, v/v) solution. From the restrained molecular dynamics calculation using NMR data, we obtained the possible conformation of buforin II in TFE/H$_2$O solution. (omitted)

A suproxide dismutase gene of Aquifex pyroprolus, a novel marine hypenhermophilic bacterium, was cloned, expressed, and characterized. The SOD of A pyrophilus (ApSOD) is an iron-containing homo-oligomeric protein with a monomeric molecular weight of 24.2 kDa. the amino acid sequence is similar to those of known Mn- and Fe-SODs from thermophilic archaea, and metal binding residues in all SOD sequences from different species are also conserved in A. pyrophilus SOD. (omitted)

The double-stranded panhandle structure of the influenza virus RNA is important for the replication, transcription and packaging into the virion of the vRNA. The solution structure of a 34-nucleotide-long RNA which contains the conserved panhandle sequences has been investigated by one- and two-dimensional NMR spectroscopies. (omitted)

Molecular docking studies were performed for a humanized HBV Pre-S2 antibody and its antigen adr. Antigen structure was taken from NMR experiment and antibody structure was determined by using homology technique. At first step, Grid search was performed for finding energetically favorable orientations antigen. (omitted)

An ectodomain of gp41, the transmembrane fusion protein of HIV, without the fusion peptide region was expressed using pET system in E. coli. The expressed protein gp41core, was isolated as inclusion body and was purified by ion-exchange chromatography after solubilized in 6M urea. The purified denatured protein was renaturated and the folded domain of gp41core was identified by the presence of the proteolysis resistence domain and a high content of ${\alpha}$-helical secondary structure. (omitted)

Previously we showed that $Ba^{2+}$ block of large conductance $Ca^{2+}$-activated $K^{+}$ (BK) channel was larger in the planar lipid bilayer formed with negatively-charged phosphatidylserine (PS) than neutral phosphatidylethanolamine (PE). In this work, have studied the blocking effect of two $K^{+}$ channel blockers with different mechanisms of action, $Ba^{2+}$ and tetraethylammonium (TEA), on BK channels of rat skeletal muscle. (omitted)itted)

Nitric oxide (NO) has been reported to have many roles in vivo ranging from the neurotransmitter in brain to the relaxant in smooth muscles. Recently, using inside-out patches, Bolotina et al. (1) showed that relaxing effect of NO is aortic smooth muscle is through direct activation of Ca2+-activated K+ channels (maxi-K), resulting in hyperpolarization. (omitted)

The activities of Maxi-K channels were recorded using inside-out patches. The application of 30 nM of non-specific G protein activator, GTP $\gamma$S, to the intracellular side of the channels increases the channel activities about 3-fold, indicating that there exist some G proteins within the patch membranes to regulate the channel activities. (omitted)

Tenecin fragments are antimicrobial and antifungal peptide from Tenebrio molitor with highly positive charged amino acid residues. To elucidate their membrane selectivity and molecular mechanism, various forms of tenecin fragments were synthesized, and their interaction with acidic phospholipid, Gram (+), fungal and human erythrocyte membrane were investigated by ANTS/DPX leakage, membrane binding and fusion assay. (omitted)

Rab3A is a synaptic vesicle-associated, GTP-binding protein that has been implicated in the regulation of neurotransmission. We show here that Ca2+/calmodulin can form a 1:1 complex with Rab3A and cause it to dissociate from synaptosomal membranes. Formation of the complex requires both the lipidated C-terminus of Rab3A and the presence of guanine nucleotide. (omitted)

Extracts were prepared from six different poisonous mushrooms in order to identify biologically active natural ligands. The effects of these extracts were examined on the microsomal $^{45}$ Ca$^{2+}$ uptake and $^{45}$ Ca$^{2+}$ release. Five out of six species apparently inhibited the activity of total microsomal ATPases prepared from the epithelial cells of pig airway. (omitted)ted)

Abnormally high $Ca^{2+}$ concentrations have been reported in the cardiac myocytes of diabetic mellitus (DM). In order to elucidate the molecular mechanisms of the intracellular $Ca^{2+}$ overload, the activities of $^{45}$ Ca$^{2+}$ uptake and $^{45}$ Ca$^{2+}$ release were measured from the vesicles of junctional SR (Heavy SR, HSR). (omitted)omitted)

Chilling-sensitive plants are damaged severly by chilling in the light. The activity of photosystem I(PSI) is known to be inhibited by low light-chilling and its iron-sulfur centers are presumed to be its primary target. In this report, the effect of chilling at 4$^{\circ}C$ in the light was investigated in the level of pigment-protein complexes in cucumber leaves compared with pea leaves. (omitted)

Adrenal chromaffin cells secrete catecholamine in response to acetylcholine. The secretory response has absolute requirement for extracellular calcium, indicating that $Ca^{2+}$ influx through voltage operated $Ca^{2+}$ channels (VOCC) is the primary trigger of the secretion cascade. Although the existence of various types of $Ca^{2+}$ channels has been explore using patch clamp techique in adrenal chromaffin cells, the contribution of different types of $Ca^{2+}$ channels to catecholamine secretion remains to be establised. (omitted)omitted)

Bovine angiogenin (bAng) is a potent blood vessel inducing protein purified from cow milk. Fluorescence spectroscopy has been used to study the interaction of bAng with actin in 50 mM Tris-HCl, pH 7.5, and 1 mM CaCl$_2$ at 25$^{\circ}C$. Actin contains four tryptophans but bAng contains no tryptophans. A 50% decrease in intrinsic fluorescence accompanied formation of the bAng/actin complex. (omitted)

Immunoserisor for the determination of LDL(Low-Density Lipoprotein) was developed by using quartz crystal microbalance(QCM) system. LDL is known to be a good indicator for the diagnosis of atherosclerosis and hypercholesterolemia. The immunosensor consists of four parts; detection cell, oscillating circuit, oscilloscope, and frequency counter, and this was interfaced with personal computer for signal processing. (omitted)

Flavin-peptides were purified from pyranose oxidase (EC 1.1.3.10) after tryptic- chymotryptic and tryptic digestion. The spectral and chromatographic properties of these flavin peptides showed that the FAD of pyranose oxidase appears to be bound, by way of the 8${\alpha}$-methylene group, to the N-l position of the imidazole ring of the histidine. Automated sequence analysis showed that the amino acid sequence of the tryptic-chymotryptic flavin-peptide from pyranose oxidase is Ser-Thr-X-Trp and that of the tryptic flavin-peptide is Met-Ser-Thr-X-Trp. (omitted)

To elucidate the mechanism for the cross-linking reaction in the glycation or Maillard reaction, we studied the reaction between proteins, and a three-carbon ${\alpha}$-ketoaldehyde, methylglyoxal. When Cu, Zn-SOD was incubated with 200 mM of methylglyoxal, the peroxidase activity as well as the superoxide dismutase activity was reduced. This reduction is accompanied by the decrease of the anion binding affinity of the enzyme. (omitted)