Purification, characterization and functional expression of a new peptide with an analgesic effect from Chinese scorpion Buthus martensii Karsch (BmK AGP-SYPU1)

In this study, a new peptide named BmK AGP‐SYPU1 with an analgesic effect was purified from the venom of Chinese scorpion Buthus martensi Karsch (BmK) through a four‐step chromatographic process. The mouse twisting test was used to identify the target peptides in every separation step. The purified BmK AGP‐SYPU1 was further qualified by RP‐HPLC and HPCE. The molecular mass determined by the MALDI‐4800‐TOF/TOF MS for BmK AGP‐SYPU1 was 7544 Da. Its primary structure of the N‐terminal was obtained using Edman degradation. The gene sequence of BmK AGP‐SYPU1 was cloned from the cDNA pool and genomic of scorpion glands, respectively, and then expressed in Escherichia coli. The sequence determination showed that BmK AGP‐SYPU1 was composed of 66 amino acid residues with a new primary structure. The metal chelating affinity column and cation exchange chromatography were used to purify the recombinant BmK AGP‐SYPU1. Consequently, the native and recombinant BmK AGP‐SYPU1 showed similar analgesic effects on mice as assayed using a mouse twisting model. These results suggested that BmK AGP‐SYPU1 is a new analgesic component found in the Chinese scorpion Buthus martensi Karsch. Copyright © 2010 John Wiley & Sons, Ltd.     

Purification and characterization of an analgesic peptide from Buthus martensii Karsch

The scorpion Buthus martensii Karsch (BmK) has been one of the indispensable materials in Chinese traditional medicine for thousands of years. In this work, an analgesic peptide was purified through four continuous chromatographic steps. The mouse twisting test was used to identify the target peptides in every separation step. The molecular weight, isoelectric point, and N-terminal residues of the purified peptide were determined. Based on the N-terminal sequence, the cDNA was also cloned by rapid amplification of cDNA ends from the cDNA pool of scorpion glands. This peptide was identical to BmK AS, an agonist of rabbit skeletal muscle ryanodine receptors. Preliminary pharmacodynamics revealed the following: the dose-effect curve plotted by the mouse twisting test showed an ED(50) of 1.42 mg/kg; and the time-effect curves plotted by a hot plate procedure showed a similar effect to the painkiller morphine. We report a purification procedure that yields substantial amounts of natural BmK AS having high activity. BmK AS has the potential to become a new analgesic medicine.     

Purification, Characterization and 1H NMR Resonance Assignment of an a－Like Neurotoxin BmK 16 from the Venom of Chinese Scor－pion Buthus martensii Karsch

A natural scorpion toxin BmK 16 was purified for the first time from the venom of the Chinese scorpion Buthus martensii Karsch (BmK) by using combined gel-filtration, ion exchange and reversed phase chromatography. The sequence of the N-terminal 8 amino acid residues was determined by Edman degradation. Using the N-terminal sequence as a tag, the database searching revealed a hit in the scorpion cDNA Bank. The sequence for N-terminal 8 amino acid residues, molecular weight and amino acid compositions of BmK 16 were identical with the calculated values according to the first 64 residues‘ se-quence of the precursor peptide alpha-neurotoxin TX16 derived from the sequence of the cDNA AF156597 (EMBL). The se-quence-specific resonance assignment of BmK 16 was achieved and the intact sequence of BmK 16 was determined as follow-ings: VRDAY IAKPH NCVYE CARNE YCNDL CTKNG AKSGY CQWVG KYGNG CWCKE LPDNV PIRVP GKCH. Furthermore, the results from the sequence homology analysis and the toxicity assays indicated that BmK 16 was an α-likescorpion neurotoxin.     

Amino Acid Sequence of an Excitatory Insect-selective Toxin (BmK IT) From Venom of the Scorpion Buthus martensi Karsch

The insect-selective neurotoxin(BmK IT) of scorpion Buthus martensi Karsch was first reduced and S-alkylated, and then digested by TPCK-trypsin and Staphylococcus aureus V-8 Protease. The enzymatic peptides were purified on TLC-plastic sheet and submitted to determine their amino acid compositions and sequences. The sequence of the 70 amino acid residues of BmK IT was established with reference to the primary structure of AaH IT, another excitatory insect-selective toxin from the venom of North African scorpion Androctonus australis Hector. About 75% of the homologous sequence was found in the molecules of BmK IT and AaH IT. It is obvious that the results contribute toward better understanding of the molecular structure characteristics, structure/activity relationship of scorpion insect-selective toxins, and they can serve as the molecular basis for utilizing the toxins as a tool to clarify molecular mechanism involved in channel gating, and to infer the possibility of developing them as new selective b     

马氏钳蝎蝎毒短肽BmK622的分离纯化和一级结构测定

应用凝胶过滤、离子交换和HPLC反相色谱法从马氏蝎粗毒中分离纯化得到蝎毒 多肽BmK622．联合运用串联质谱法和Edman降解法，鉴定了KmK622N端19个残基的序 列，经过数据库检索，发现数据库中用cDNA克隆方法鉴定了序列的马氏钳蝎蝎毒短 肽BmTX3一级序列N端19个残基与BmK622已测定的N端19个残基序列完全相同， BmK622的分子量测定和氨基酸组成分折的结果表明，BmK22与BmTX3分子量相同、氨 基酸组成一致，从而BmK22的一级结构为：GFLID VKCFA SSECW TACKK VTGSG QGKCQ NNQCR CY．     

Discovery of a New Analgesic Peptide,Leptucin, from the Iranian Scorpion,Hemiscorpius lepturus

Hemiscorpius lepturus scorpion stings do not induce considerable pain based on epidemiological surveys conducted in the southwest part of Iran. Accordingly, this study was aimed to identify the analgesic molecule in H. lepturus venom by analyzing a cDNA library of the scorpion venom gland looking for sequences having homology with known animal venom analgesic peptides. The analgesic molecule is a cysteine rich peptide of 55 amino acids. the synthetic peptide was deprotected and refolded. RP-HPLC, Ellman’s, and DLS assays confirmed the refolding accuracy. Circular dichroism (CD) showed helix and beta sheet contents. This peptide, called leptucin, demonstrated 95% analgesic activity at the dose of 0.48 mg/kg in hot plate assay. Leptucin at the doses of 0.32, 0.48, and 0.64 mg/kg showed 100% activity in thermal tail flick test. No hemolysis or cytotoxicity was observed at 8 and 16 μg. Histopathology evaluations indicated no hepatotoxicity, nephrotoxicity, and cardiotoxicity. We thus report that leptucin is the analgesic agent of H. lepturus venom. Regarding the high in vivo efficacy of leptucin and the fact it shows no observable toxicity, it could be suggested as a drug lead in a preclinical study of acute pain as well as the study of its mechanism of action.     

Expression and Characterization of a Novel Enantioselective Lipase from Aspergillus fumigatus

A 1,080-bp cDNA (CGMCC 2873) encoding of a cold-active lipase of Aspergillus fumigatus (AFL67) was cloned and expressed in Escherichia coli for the first time. The new lipase, AFL67, was one-step purified by 8.30 folds through Ni?CNTA affinity chromatography with a recovery of 86.8?%. The specific activity of purified AFL67 was 449?U?mg^?1 on p-NP hexanoate. AFL67 preferentially hydrolyzed p-nitrophenyl esters of short- and medium-chain fatty acids, with p-nitrophenyl hexanoate the maximum. The optimum temperature and pH was 15?°C and 7.5, respectively. The purified AFL67 was stable at 10?C25?°C for 30?min, and in the pH range of 6.0?C9.0 for 16?h (at 4?°C). Its activity was increased by 47 and 50?%, in the presence of 10?% (v/v) ethanol and isopropanol, respectively. The new lipase AFL67 highly enantioselectively deacylated (S)-??-acetoxyphenylacetic acid (APA) and o-Cl-APA, m-Cl-APA, and p-Cl-APA to (S)-mandelic acid and its derivates. These features render this cold-active novel lipase AFL67 attractive for biotechnological applications in the field of enantioselective synthesis of chiral mandelic acids, o-acylated mandelic acids, and their derivates and detergent additives.     

Arginylation and methylation double up to regulate nuclear proteins and nuclear architecture in vivo

Protein arginylation and arginine methylation are two posttranslational modifications of emerging importance that involve Arg residues and their modifications. To test a hypothesis that posttranslationally added arginines can be methylated, we used high-precision mass spectrometry and metabolic labeling to find whether posttranslationally added arginines can serve as methylation sites. We identified?a number of proteins in?vivo, on which posttranslationally added Arg have undergone mono- and dimethylation. This double modification predominantly affects the chromatin-containing nuclear fraction and likely plays an important regulatory role in chromatin-associated proteins. Moreover, inhibition of arginylation and Arg methylation results in?a significant reduction of the nucleus size in cultured cells, suggesting changes in chromatin compaction and nuclear architecture. Our findings suggest?a functional link between protein regulation by arginylation and methylation that affects nuclear structure in?vivo.     

Engineering Plant Alternative Oxidase Function in Mammalian Cells: Substitution of the Motif-like Sequence ENV for QDT Diminishes Catalytic Activity of Arum concinnatum AOX1a Expressed in HeLa Cells

Alternative oxidase (AOX) is a nonproton motive quinol–oxygen oxidoreductase which is a component of the mitochondrial respiratory chain in higher plants. In this study, we have characterized the catalytic activity and regulatory behaviors of Arum concinnatum AOX isoforms, namely AcoAOX1a and AcoAOX1b, and their artificial mutants in HeLa cells. We demonstrated that substitution of the motif-like sequence ENV on the C-terminal half of AcoAOX1a for QDT diminishes its activity and proposed that the innate inactivity of AcoAOX1b in HeLa cells is, at least in part, attributable to its QDT motif. Furthermore, we show that introduction of F130L in the hydrophilic N-terminal extension of AcoAOX1a resulted in greater activity in the presence of pyruvate. This result indicates that functional significance of the N-terminal extension is not particular to the conventional regulatory cysteine. On the basis of these findings, we discuss new insights into the structural integrity of AOX in HeLa cells and the applicability of mammalian cells for functional analysis of this enzyme.     

Recombinant Expression and Characterization of l-Asparaginase II from a Moderately Thermotolerant Bacterial Isolate

A moderately thermotolerant bacterium belonging to Enterobacteriaceae, which can grow at 44.5?°C, was isolated from cow dung; l-asparaginase II gene was isolated by PCR, cloned, and expressed in pET 20b with pelB leader sequence and 6× Histidine tag at the C-terminal end. The active protein from the soluble sonicated fraction was purified through nickel affinity chromatography. After characterization, the purified protein showed optimum activities at a temperature of 37?°C and in a buffer system of pH?6 to 7. The enzyme exhibited thermostability at 50?°C with a 33% and 28% of activity retention after 45 and 60?min. The kinetic parameters for the enzyme were calculated from Lineweaver?CBurk plot, and K _m and V _max were 0.89?mM and 0.18?U/mg, respectively.     

Purification and Properties of a Thermostable Xylanase GH 11 from Penicillium occitanis Pol6

An extracellular, endo-??-1,4-xylanase was purified to homogeneity from the culture filtrate of the filamentous fungus Penicillium occitanis Pol6, grown on oat spelt xylan. The purified enzyme (PoXyn2) showed a single band on SDS?CPAGE with an apparent molecular weight of 30?kDa. The xylanase activity was optimal at pH?3.0 and 65?°C. The specific activity measured for oat spelt xylan was 2,368?U?mg^?1. The apparent K _m and V _max values were 8.33?mg?ml^?1 and 58.82???mol?min^?1?ml^?1, respectively, as measured on oat spelt xylan. Thin-layer chromatography experiments revealed that purified PoXyn2 degrades xylan in an endo-fashion releasing xylobiose as main end product. The genomic DNA and cDNA encoding this protein were cloned and sequenced. This PoXyn2 presents an open reading frame of 962?bp, not interrupted by any introns and encoding for a mature protein of 320 amino acids and 29.88?kDa.     

Crystal Structures of the Plant Phospholipase A1 Proteins Reveal a Unique Dimerization Domain

Phospholipase is an enzyme that hydrolyzes various phospholipid substrates at specific ester bonds and plays important roles such as membrane remodeling, as digestive enzymes, and the regulation of cellular mechanism. Phospholipase proteins are divided into following the four major groups according to the ester bonds they cleave off: phospholipase A1 (PLA1), phospholipase A2 (PLA2), phospholipase C (PLC), and phospholipase D (PLD). Among the four phospholipase groups, PLA1 has been less studied than the other phospholipases. Here, we report the first molecular structures of plant PLA1s: AtDSEL and CaPLA1 derived from Arabidopsis thaliana and Capsicum annuum, respectively. AtDSEL and CaPLA1 are novel PLA1s in that they form homodimers since PLAs are generally in the form of a monomer. The dimerization domain at the C-terminal of the AtDSEL and CaPLA1 makes hydrophobic interactions between each monomer, respectively. The C-terminal domain is also present in PLA1s of other plants, but not in PLAs of mammals and fungi. An activity assay of AtDSEL toward various lipid substrates demonstrates that AtDSEL is specialized for the cleavage of sn-1 acyl chains. This report reveals a new domain that exists only in plant PLA1s and suggests that the domain is essential for homodimerization.     

Structure-activity relationships (SAR) of [D-Arg(2)]dermorphin(1-4) analogues,N(alpha)-amidino-Tyr-D-Arg-Phe-X

In investigating the development of compounds with potent analgesic effects after oral administration, 74 C-terminal analogues (N(alpha)-amidino-Tyr-D-Arg-Phe-X), based on the structure of N(alpha)-amidino-Tyr-D-Arg-Phe-Me beta Ala-OH (ADAMB), were synthesized. Their analgesic activity was evaluated using the mouse-tail pressure test after both subcutaneous and oral administration, and the structure-activity relationships (SAR) were examined in detail. The results clearly indicated that compounds containing beta-amino acid without a side chain at the X position are preferable for expression of potent analgesic activity, and that the free carboxyl group is superior in its analgesic activity to that of the esterified or amidated carboxy group at the C-terminal. In addition, N-methylation of the amide bond at the 4th position contributed to improved analgesic activity. These results indicated that the strong and long-lasting analgesic effect of ADAMB is expressed by the synergistic effects of N(alpha)-amidination, the N-methylation of the amide bond at the 4th position and the carbon chain length (beta-Ala) of the residue at the 4th position, and that this is the most suitable structure.     

The effect of high dose of gamma-irradiation on residual radicals concentration in ultra-high molecular weight polyethylene (UHMWPE) in the presence of vitamin E

Powder samples of UHMWPE (GUR 1020) containing 0.1% by wt. vitamin E (??-tocopherol, ??-T) were irradiated at room temperature in air for doses of 30-kGy, 65-kGy or 100-kGy (⁶⁰Co). After irradiation, they were stored at ?78.5°C (dry ice temperature) for one year and then opened to air at room temperature. Following the decay of the primary alkyl and allyl radicals (at room temperature in air), growth of the carbon-centered polyenyl R1 (?^·CH?CH=CH?, m ?? 3), and the oxygen-centered dior tri-enyl R2 (?^·OCH?CH=CH? _m , m ?? 3) residual radicals were measured for eight weeks. An X-band electron spin resonance (ESR) spectrometer was used for radical measurements. The initial relative radical concentrations (R2/R1) were found to be 10.13, 4.6 and 3.7 for the 65-kGy, 30-kGy and 100-kGy samples, respectively. R1 and R2 were both found to grow significantly in the 65-kGy samples while they grew only slightly in the 30-kGy and 100-kGy samples. In 65-kGy sample, R1 grew faster than R2 and the relative concentration R2/R1 was reduced from 10.13 to 2.9 for the 65-kGy sample while that for the 30-kGy and 100-kGy samples reduced only slightly, from 4.6 to 3.5 and 3.7 to 3.2, respectively. The behavior of the residual radicals can be explained by Raman spectroscopic data which suggest that the 65-kGy samples had a higher percentage of amorphous regions when compared to the 30-kGy or 100-kGy (21.7% compared to 15.7% or 17.9%) and also suggest a lower percentage of inter-phase regions (16.4% compared to 25.6% or 17.5%) and a lower level of structural disorder (0.26% compared to 0.44% or 0.27%).     

Conformations of protonated gas-phase bradykinin ions: evidence for intramolecular hydrogen bonding

The post-source decay of bradykinin, Lys1-bradykinin, des-Arg1-bradykinin, des-Arg9-bradykinin and [D-Phe7]-bradykinin [M + H]+ ions was examined in order to assertain the influence of secondary structure on peptide ion dissociation. Fragment ions corresponding to the elimination of H2O and HN=C=NH are observed in the product ion mass spectra of Lys1-bradykinin and des-Arg1-bradykinin but not in the spectra of bradykinin or des-Arg9-bradykinin. Cleavage reactions at the Phe-Ser and/or Ser-Pro bonds are observed for all peptide [M + H]+ ions with the exception of des-Arg9-bradykinin. The product ions arising from the processes described above are rationalized in terms of the intramolecular solvation of the protonated guanidino groups of the arginines. The strongest intramolecular interaction appears to be a proton bridge between the guanidino groups of the N- and C-terminal arginines in bradykinin. In addition, increased abundances of fragment ions in the vicinity of Ser-Pro may be attributed to intramolecular solvation of the protonated C-terminal guanidino group by the Ser-Pro portion of the molecule. This self-solvation of the ionizing proton leads to a gas-phase peptide conformation that is supported by solution-phase NMR studies at elevated temperatures and in non-polar solvents but which is different from the conformation in polar solvents.     

Microcalorimetric investigation of the antibacterial activity of curcumin on Staphylococcus aureus coupled with multivariate analysis

The antibacterial effect of Curcumin on Staphylococcus aureus growth was evaluated by microcalorimetry. The heat flow power?Ctime curves and nine quantitative parameters of the S. aureus growth were applied to investigate the inhibitory effect with Curcumin. By analyzing these curves and some quantitative parameters using multivariate analytical methods, similarity analysis and principal component analysis, the antibacterial activity of Curcumin on S. aureus could be accurately evaluated from the change of the two main parameters, the second exponential growth rate constant k ₂ and the maximum heat flow power P _m ² . The main two thermal parameters played more important role in the evaluation: at low concentration (0?C10.5???g?mL^?1), Curcumin hardly influence the growth of S. aureus, while at high concentration (10.5?C43.4???g?mL^?1) it could notably inhibit the growth. All these illustrated that the antibacterial activity of Curcumin on S. aureus was enhanced with the increase of the concentration of this compound. This study might provide an useful method and idea accurately evaluate the antibacterial effects of Curcumin, which provides some useful methods for evaluate the nature antibacterial agents.     

A New Aminopeptidase from the Keratin-Degrading Strain Streptomyces fradiae var. k11

An aminopeptidase gene fragment was isolated from a keratin-degrading strain, Streptomyces fradiae var. k11, by PCR amplification using a degenerate primer set designed based on the partial amino acid sequence of the native enzyme. The gene, designated sfap, encoded a polypeptide of 461 amino acids comprised of three domains: a signal peptide, a mature region, and a C-terminal propeptide. The aminopeptidase, SFAP, had highest amino acid sequence identity (79%) with a putative aminopeptidase from Streptomyces griseus subsp. griseus NBRC 13350. The gene with and without C-terminal propeptide was successfully overexpressed in Escherichia coli BL21 (DE3), and the gene without C-terminal propeptide encoded a functional enzyme. Purified recombinant SFAP exhibited optimal activity at pH 8.0 and 60 °C, and retained >60% peak activity over a broad range of temperature. The enzyme was thermal and pH stable, and showed metalloprotease characteristics, which was inhibited by EDTA but activated by Ca²⁺ and Co²⁺. This is the first study to report the gene cloning and expression of a leucine aminopeptidase from S. fradiae.     

Essential Role of the N- and C-terminals of Laccase from Pleurotus florida on the Laccase Activity and Stability

POXA1b is the most thermostable laccase isoenzyme from Pleurotus ostreatus. POXA1b is remarkably stable at alkaline pH (the t_1/2 at pH 10 was 30 days), and its C-terminal affects its catalytic and stability properties. We cloned POXA1c from P. florida, which showed 99 % identity with POXA1b. POXA1c was functionally expressed in Pichia pastoris. The functions of the N and C termini of POXA1c were investigated using site-directed mutagenesis. Compared with POXA1c, the N-terminal R5V site effectively increased the specific activities for 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and guaiacol by 2- and 3.5-fold, respectively. A C-terminal truncated mutant, POXA1c△13, also increased the specific activities for ABTS and guaiacol by 2.3- and 3.4-fold, respectively. A double mutant, POXA1cΔ13-R5V, combined the R5V and △13 effects. The specific activity of this double mutant for ABTS was 1,321 U/mg, which indicated a 4-fold increase compared with the wild type. The role of residue V5 on laccase catalytic properties was also observed for laccases from Trametes versicolor and Rigidoporus lignosus. The specific activities of the V5R of the laccases from T. versicolor and R. lignosus were half of that of the wild type. The pH and thermal stability analysis of POXA1c and its mutants showed that the enzymes were remarkably stable because they showed 63 % residual activity after incubation for 108 h at 30 °C over a pH range of 4.5 to 9.0. Similar results were observed for POXA1cΔ13-R5V. POXA1cΔ13-R5V can be widely used in industrial biotechnology because of its excellent catalytic properties.     

Calorimetric studies on the thermal decomposition of tri n-butyl phosphate-nitric acid systems

Thermal decomposition of neat TBP, acid-solvates (TBP·1.1HNO₃, TBP·2.4HNO₃) (prepared by equilibrating neat TBP with 8 and 15.6?M nitric acid) with and without the presence of additives such as uranyl nitrate, sodium nitrate and sodium nitrite, mixtures of neat TBP and nitric acid of different acidities, 1.1?M TBP solutions in diluents such as n-dodecane (n-DD), n-octane and isooctane has been studied using an adiabatic calorimeter. Enthalpy change and the activation energy for the decomposition reaction derived from the calorimetric data wherever possible are reported in this article. Neat TBP was found to be stable up to 255?°C, whereas the acid-solvates TBP·1.1HNO₃ and TBP·2.4HNO₃ decomposed at 120 and 111?°C, respectively, with a decomposition enthalpy of ?495.8?±?10.9 and ?1115.5?±?8.2?kJ?mol^?1 of TBP. Activation energy and pre exponential factor derived from the calorimetric data for the decomposition of these acid-solvates were found be 108.8?±?3.7, 103.5?±?1.4?kJ?mol^?1 of TBP and 6.1?×?10¹⁰ and 5.6?×?10⁹?S^?1, respectively. The thermochemical parameters such as, the onset temperature, enthalpy of decomposition, activation energy and the pre-exponential factor were found to strongly depend on acid-solvate stoichiometry. Heat capacity (C _p ), of neat TBP and the acid-solvates (TBP·1.1HNO₃ and TBP·2.4HNO₃) were measured at constant pressure using heat flux type differential scanning calorimeter (DSC) in the temperature range 32?C67?°C. The values obtained at 32?°C for neat TBP, acid-solvates TBP·1.1HNO₃ and TBP·2.4HNO₃ are 1.8, 1.76 and 1.63?J?g^?1?K^?1, respectively. C _p of neat TBP, 1.82?J?g^?1?K^?1, was also measured at 27?°C using ??hot disk?? method and was found to agree well with the values obtained by DSC method.     

Extracellular Production of Novel Halotolerant, Thermostable, and Alkali-Stable Carboxymethyl Cellulase by Marine Bacterium Marinimicrobium sp. LS-A18

Cellulases which are active and stable under extreme conditions have attracted considerable attention because of their potential industrial applications. Marinimicrobium sp. LS-A18 showed high extracellular carboxymethylcellulase (CMCase) activity when grown on mineral salt medium containing carboxymethylcellulose as the sole carbon source. Maximum CMCase activity was obtained at 55°C and pH 7.0 in the absence of NaCl. Under the optimized fermentation conditions, the yield of CMCase was increased up to 2.5 U/ml, which was 3.1-fold higher than that before optimization. The enzyme retained 84?% of residual activity after incubation at 60°C for 1?h and more than 88?% of residual activity after incubation for 72?h in the presence of different pH (5?C11) and NaCl concentrations (0?C25?%, w/v), indicating it was halotolerant, thermostable and alkali-stable. These characteristics made the CMCase from Marinimicrobium sp. LS-A18 as a potentially novel biocatalyst in biotechnological and industrial applications.