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1.
蝎短肽链神经毒素研究进展 总被引:2,自引:0,他引:2
对蝎短肽链神经毒素结构与功能研究进展作了简要的论述,蝎毒中富含短肽链神经毒素,至今已经分离纯化到60多种,它们的大小介于28-41个氨基酸残基之间,分子中含有3-4对二硫键,空间结构紧密,这些毒素可以特异性地与K+,Cl-和Ca2 等离子通道相结合,由于它们对离子通道的选择性,这些毒素在药理学和神经生物学中已经得到了广泛的应用。 相似文献
2.
3.
《Peptides》2016
Kbot55 is a 39 amino acid peptide isolated from the venom of the Tunisian scorpion Buthus occitanus tunetanus. This peptide is cross-linked by 3 disulfide bridges and has a molecular mass of 4128.65 Da. Kbot55 is very low represented in the venom and thus represents a challenge for biochemical characterization. In this study, Kbot55 has been subjected to a screening on ion channels expressed in Xenopus laevis oocytes. It was found that Kbot55 targets voltage-gated potassium channels with high affinity. Kbot55 shows very low amino acid identity with other scorpion potassium toxins and therefore was considered a bona fide novel type of scorpion toxin. Sequence alignment analysis indicated that Kbot55 is the first representative of the new α-Ktx31 subfamily and therefore was classified as α-Ktx31.1. 相似文献
4.
Purification and Characterization of Nk‐3FTx: A Three Finger Toxin from the Venom of North East Indian Monocled Cobra
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Diganta Das Maitreyee Sharma Hemanga Kumar Das Partha Pratim Sahu Robin Doley 《Journal of biochemical and molecular toxicology》2016,30(2):59-70
Snake venom three finger toxins (3FTxs) are a non‐enzymatic family of venom proteins abundantly found in elapids. We have purified a 7579.5 ± 0.591 Da 3FTx named as Nk‐3FTx from the venom of Naja kaouthia of North East India origin. The primary structure was determined by a combination of N‐terminal sequencing and electrospray ionization liquid chromatography‐mass spectrometry/mass spectrometry. Biochemical and biological characterization reveal that it is nontoxic to human cell lines and exhibit mild anticoagulant activity when tested on citrated human plasma. Nk‐3FTx was found to affect the compound action potential (CAP) and nerve conduction velocity of isolated toad sciatic nerve. This is the first report of a non‐conventional 3FTx from Naja kaouthia venom that reduces CAP for its neurotoxic effect. Further studies can be carried out to understand the mechanism of action and to explore its potential therapeutic application. 相似文献
5.
All the neurotoxic phospholipases A2 present in whole Vipera russelli venom were precipitated selectively from other non-neurotoxic phospholipases A2 and non-phospholipases A2 fractions using antibodies (anti PL-V Ig) raised against one of the purified neurotoxic phospholipases A2 (VRV PL-V). These neurotoxins were identified and isolated in their homogeneous form by chromatographic and electrophoretic methods. The present report of selective isolation and purification of all the neurotoxic phospholipases A2 of V. russelli venom is first of its kind. 相似文献
6.
Structure and pharmacology of spider venom neurotoxins 总被引:16,自引:0,他引:16
Spider venoms are complex mixtures of neurotoxic peptides, proteins and low molecular mass organic molecules. Their neurotoxic activity is due to the interaction of the venom components with cellular receptors, in particular ion channels. Spider venoms have proven to be a rich source of highly specific peptide ligands for selected subtypes of potassium, sodium and calcium channels, and these toxins have been used to elucidate the structure and physiological roles of the channels in excitable and non-excitable cells. Spider peptides show great variability in their pharmacological activity and primary structure but relative homogeneity in their secondary structure. Following diverse molecular evolution mechanisms, and in particular selective hypermutation, short spider peptides appear to have functionally diversified while retaining a conserved molecular scaffold. This paper reviews the composition and pharmacology of spider venoms with emphasis on polypeptide toxin structure, mode of action and molecular evolution. 相似文献
7.
Arnon T Potikha T Sher D Elazar M Mao W Tal T Bosmans F Tytgat J Ben-Arie N Zlotkin E 《Insect biochemistry and molecular biology》2005,35(3):187-195
Long-chain neurotoxins derived from the venom of the Buthidae scorpions, which affect voltage-gated sodium channels (VGSCs) can be subdivided according to their toxicity to insects into insect-selective excitatory and depressant toxins (beta-toxins) and the alpha-like toxins which affect both mammals and insects. In the present study by the aid of reverse-phase HPLC column chromatography, RT-PCR, cloning and various toxicity assays, a new insect selective toxin designated as BjalphaIT was isolated from the venom of the Judean Black Scorpion (Buthotus judaicus), and its full primary sequence was determined: MNYLVVICFALLLMTVVESGRDAYIADNLNCAYTCGSNSYCNTECTKNGAVSGYCQWLGKYGNACWCINLPDKVPIRIPGACR (leader sequence is underlined). Despite its lack of toxicity to mammals and potent toxicity to insects, BjalphaIT reveals an amino acid sequence and an inferred spatial arrangement that is characteristic of the well-known scorpion alpha-toxins highly toxic to mammals. BjalphaITs sharp distinction between insects and mammals was also revealed by its effect on sodium conductance of two cloned neuronal VGSCs heterloguously expressed in Xenopus laevis oocytes and assayed with the two-electrode voltage-clamp technique. BjalphaIT completely inhibits the inactivation process of the insect para/tipE VGSC at a concentration of 100 nM, in contrast to the rat brain Na(v)1.2/beta1 which is resistant to the toxin. The above categorical distinction between mammal and insect VGSCs exhibited by BjalphaIT enables its employment in the clarification of the molecular basis of the animal group specificity of scorpion venom derived neurotoxic polypeptides and voltage-gated sodium channels. 相似文献
8.
Quinton L Demeure K Dobson R Gilles N Gabelica V De Pauw E 《Journal of proteome research》2007,6(8):3216-3223
Animal venoms are highly complex mixtures that can contain many disulfide-bridged toxins. This work presents an LC-MALDI approach allowing (1) a rapid classification of toxins according to their number of disulfide bonds and (2) a rapid top-down sequencing of the toxins using a new MALDI matrix enhancing in-source decay (ISD). The crude venom is separated twice by LC: the fractions of the first separation are spotted on the MALDI matrix alpha-cyano-4-hydroxycinnamic acid (CHCA) and the others using 1,5-diaminonaphthalene (1,5-DAN). CHCA spots are more convenient for obtaining a precise mass fingerprint of a large number of peptides; however, the analysis of 1,5-DAN spots allows the number of disulfide bridges to be counted owing to their partial in-plume reduction by this particular matrix. Subsequently, the disulfide bonds of all peptides present in the crude venom were reduced by an excess of tris(carboxyethyl)phosphine before the LC separation and were subjected to the same analysis in CHCA and 1,5-DAN. Toxins were sequenced using a TOF/TOF analysis of metastable fragments from CHCA spots and ISD fragmentation from 1,5-DAN spots. Novel conotoxin sequences were found using this approach. The use of 1,5-DAN for ISD top-down sequencing is also illustrated for higher molecular weight toxins such as snake cardiotoxins and neurotoxins (>6500 Da), where sequence coverage >70% is obtained from the c-ion series. 相似文献
9.
In the current study, two peptides with antioxidant properties were purified from skin protein hydrolysates of horse mackerel
(Magalaspis cordyla) and croaker (Otolithes ruber) by consecutive chromatographic fractionations including ion exchange chromatography and gel filtration chromatography. By
electron spray ionization double mass spectrometry (ESI-MS/MS), the sequence of the peptide from the skin protein hydrolysate
of horse mackerel was identified to be Asn-His-Arg-Tyr-Asp-Arg (856 Da) and that of croaker to be Gly-Asn-Arg-Gly-Phe-Ala-Cys-Arg-His-Ala
(1101.5 Da). The antioxidant activity of these peptides was tested by electron spin resonance (ESR) spectrometry using 1-diphenyl-2-picryl
hydrazyl (DPPH·) and hydroxyl (OH·) radical scavenging assays. Both peptides exhibited higher activity against polyunsaturated fatty acid (PUFA) peroxidation
than the natural antioxidant α-tocopherol. These results suggest that the two peptides isolated from the skin protein hydrolysates
of horse mackerel and croaker are potent antioxidants and may be effectively used as food additives and as pharmaceutical
agents. 相似文献
10.
Pc16a, the first characterized peptide from Conus pictus venom, shows a novel disulfide connectivity
Van Der Haegen A Peigneur S Dyubankova N Möller C Marí F Diego-García E Naudé R Lescrinier E Herdewijn P Tytgat J 《Peptides》2012,34(1):106-113
A novel conotoxin, pc16a, was isolated from the venom of Conus pictus. This is the first peptide characterized from this South-African cone snail and it has only 11 amino acid residues, SCSCKRNFLCC*, with the rare cysteine framework XVI and a monoisotopic mass of 1257.6Da. Two peptides were synthesized with two possible conformations: globular (pc16a_1) and ribbon (pc16a_2). pc16a_1 co-eluted with the native peptide, which indicates a disulfide connectivity I-III, II-IV. The structure of pc16a_1 was determined by NMR. Both synthetic peptides were used to elucidate the biological activity. Bioassays were performed on crickets, ghost shrimps, larvae of the mealworm beetle and mice, but no effect was seen. Using two-electrode voltage clamp, a range of voltage-gated ion channels (Na(v) and K(v)) and nicotinic acetylcholine receptors were screened, but again no activity was found. Hence, the specific target of pc16a still remains to be discovered. 相似文献
11.
Frank Denis Torres-Huaco Luis Alberto Ponce-Soto Daniel Martins-de-Souza Sergio Marangoni 《The protein journal》2010,29(6):407-416
BmHF-1, from the venom of Bothrops marajoensis, was purified by Sephadex G-75 and HPLC-RP on μ-Bondapak C-18 column chromatography. It presented a molecular mass of 27162.36 Da
determined by MALDI-TOF MS. BmHF-1 had a sequence of 238 residues of amino acids. The multiple alignment of its amino acid
sequence and those of other snake venom metalloproteinases showed high structural similarity, mainly among P–I class. The
enzyme initially cleaves the Aα-chain of fibrinogen, followed by the Bβ-chain, and shows no effects on the γ-chain. BmHF-1
had, caseinolytic and weakly hemorrhagic activities, which were inhibited by EDTA. In contrast, PMSF did not affect these
activities. The caseinolytic activity of BmHF-1 had a pH optimum of 8.0 and was stable in solution up to 40 °C; activity was
completely lost at ≥70 °C. The proteolytic activity was also inhibited by sDa (opossum sera) and Da2-1, Da2-II, antihemorrhagic
factors isolated from the opossum sera of Didelphis albiventris. BmHF-1 presents weak hemorrhagic activity, with a MHD of 41.14 μg and it induces dose-dependent edema. We could concluded
that, despite its weak hemorrhagic activity, BmHF-1 contributes to local tissue damage by inducing edema, releasing pharmacologically
active mediators from protein precursors due to its enzymatic action. 相似文献
12.
A. A. Kruglikova 《Journal of Evolutionary Biochemistry and Physiology》2011,47(6):534-542
The present study deals with molecular nature and peculiarities of the functioning of two main protective systems of larvae
Lucilia sericata—the antimicrobial compounds of haemolymph and exosecretion released by feeding larvae into environment. In the haemolymph
of larvae undergone to bacterial infestation, the chromato-masspectrometry methods identified a set of inducible antibacterial
peptides including defensins (3844, 4062, and 4117 Da), P-peptide (3043 Da), and four new polypeptides (3235, 3702, 3746,
and 3768 Da). The exosecretion of Lucilia sericata maggots contains the peptides analogous or identical to the haemolymph antimicrobial peptides (diptericins: 8882 Da and 9025
Da), high molecular compounds of the peptide nature (6466 Da, 6633 Da, 5772 Da, 8631 Da, etc.) differing from the known haemolymph
components, and the low molecular compounds (130–700 Da). The spectrum of exosecretion bactericidal activity includes the
representatives of various groups of bacteria including pathogen the most actual from the medical point of view-the methicillin-resistant
Staphylococcus aureus that does not have anti-staphylococcal activity in contrast to haemolymph. The exosecretion components suppressing growth
and development of this staphylococcus represent the substances of low molecular mass (from 160 to 1020 Da). The performed
studies characterize the strategies used by “surgical maggots” for protection from pathogens and for suppression of microbial
competitors, and allow better understanding of molecular mechanisms of larval therapy of purulent infectious diseases. These
studies in perspective can serve the basis for creation of the principally new drugs for struggle with usual and antibiotics-resistant
bacterial infections. 相似文献
13.
《Peptides》2013
Opisthacanthus cayaporum belongs to the Liochelidae family, and the scorpions from this genus occur in southern Africa, Central America and South America and, therefore, can be considered a true Gondwana heritage. In this communication, the isolation, primary structure characterization, and K+-channel blocking activity of new peptide from this scorpion venom are reported. OcyKTx2 is a 34 amino acid long peptide with four disulfide bridges and molecular mass of 3807 Da. Electrophysiological assays conducted with pure OcyKTx2 showed that this toxin reversibly blocks Shaker B K+-channels with a Kd of 82 nM, and presents an even better affinity toward hKv1.3, blocking it with a Kd of ∼18 nM. OcyKTx2 shares high sequence identity with peptides belonging to subfamily 6 of α-KTxs that clustered very closely in the phylogenetic tree included here. Sequence comparison, chain length and number of disulfide bridges analysis classify OcyKTx2 into subfamily 6 of the α-KTx scorpion toxins (systematic name, α-KTx6.17). 相似文献
14.
Pandinus imperator scorpion venom blocks voltage-gated potassium channels in GH3 cells 总被引:1,自引:1,他引:0
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We examined the effects of Pandinus imperator scorpion venom on voltage-gated potassium channels in cultured clonal rat anterior pituitary cells (GH3 cells) using the gigohm-seal voltage-clamp method in the whole-cell configuration. We found that Pandinus venom blocks the voltage-gated potassium channels of GH3 cells in a voltage-dependent and dose-dependent manner. Crude venom in concentrations of 50-500 micrograms/ml produced 50-70% block of potassium currents measured at -20 mV, compared with 25-60% block measured at +50 mV. The venom both decreased the peak potassium current and shifted the voltage dependence of potassium current activation to more positive potentials. Pandinus venom affected potassium channel kinetics by slowing channel opening, speeding deactivation slightly, and increasing inactivation rates. Potassium currents in cells exposed to Pandinus venom did not recover control amplitudes or kinetics even after 20-40 min of washing with venom-free solution. The concentration dependence of crude venom block indicates that the toxins it contains are effective in the nanomolar range of concentrations. The effects of Pandinus venom were mimicked by zinc at concentrations less than or equal to 0.2 mM. Block of potassium current by zinc was voltage dependent and resembled Pandinus venom block, except that block by zinc was rapidly reversible. Since zinc is found in crude Pandinus venom, it could be important in the interaction of the venom with the potassium channel. We conclude that Pandinus venom contains toxins that bind tightly to voltage-dependent potassium channels in GH3 cells. Because of its high affinity for voltage-gated potassium channels and its irreversibility, Pandinus venom may be useful in the isolation, mapping, and characterization of voltage-gated potassium channels. 相似文献
15.
Kaoutar Bayoub Ilham Mardad Emna Ammar Aurelio Serrano Abdelaziz Soukri 《Current microbiology》2011,62(2):479-485
Strain 3D, isolated from fermented traditional Moroccan dairy product, and identified as Enterococcus faecium, was studied for its capability to produce two bacteriocins acting against Listeria monocytogenes. Bacteriocins 3 Da and 3Db were heat stable inactivated by proteinase K, pepsin, and trypsin but not when treated with catalase.
The evidenced bacteriocins were stable in a wide pH range from 2 to 11 and bactericidal activity was kept during storage at
4°C. However, the combination of temperature and pH exhibited a stability of the bacteriocins. RP-HPLC purification of the
anti-microbial compounds shows two active fractions eluted at 16 and 30.5 min, respectively. Mass spectrometry analysis showed
that E. faecium 3D produce two bacteriocins Enterocin 3 Da (3893.080 Da) and Enterocin 3Db (4203.350 Da). This strain is food-grade organism
and its bacteriocins were heat-stable peptides at basic, neutral, and acid pH: such bacteriocins may be of interest as food
preservatives. 相似文献
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17.
α-Casein group of proteins makes up to 65% of the total casein and consists of αS1- casein, αS2- casein and other related proteins. Among all the proteases employed, chymotryptic peptides showed maximum inhibition for
angiotensin converting enzyme (ACE). The degree of hydrolysis and release kinetics of the peptides during chymotrypsin hydrolysis
was compared with biological activity and the potent peptides fractions were identified. The crude fraction obtained after
110 min of hydrolysis shows multifunctional activities, like ACE inhibition, antioxidant activity, prolyl endopeptidase inhibitory
activity and antimicrobial activities. This fraction was further purified by HPLC and sequenced by mass spectra. This fraction
constituted peptides with molecular weights of 1,205, 1,718 Da respectively. The sequencing of peptides by MALDI-TOF MS/MS
shows sequences QKALNEINQF and TKKTKLTEEEKNRL from α-S2 casein. 相似文献
18.
Randazzo-Moura P Ponce-Soto LA Rodrigues-Simioni L Marangoni S 《The protein journal》2008,27(6):355-362
Bp-12 was isolated from Bothrops pauloensis snake venom in only one chromatographic step in reverse phase HPLC on μ-Bondapack C-18. The molecular mass of 13,789.56 Da
was determined by mass spectrometry. The amino acids composition showed that Bp-12 presented high content of Lys, Tyr, Gly,
Pro, and 14 half-Cys residues, typical of a basic PLA2. The sequence of Bp-12 contains 122 amino acid residues: SLFELGKMIL QETGKNPAKS LGAFYCYCGW GSQGQPKDAV DRCCYVHKCC YKKITGCNPK
KDRYSYSWKD KTLVCGEDNS CLKELCECDK AVAICLRENL NTYNKKYRYF LKPLCKKADA AC, with a pI value of 8.55 and with a high homology with Lys49 PLA2 from other snake venoms. In mouse phrenic nerve-diaphragm, the time needed for 50% paralysis was: 45 ± 6 min (1.4 μM) and
16 ± 6 min (3.6 μM). Bp-12 can induce indirect and directly blocked evoked twitches, even in the preparations in which Ca2+ is replaced by Sr2+, being the addition of d-tubocurarine required for direct blocking. These results identify Bp-12 as a new member of the Lys49
PLA2 family and shows that this toxin might contribute to the effects of the crude venom on the neuromuscular junction. 相似文献
19.
《Peptides》2016
Ts19 Fragment II (Ts19 Frag-II) was first isolated from the venom of the scorpion Tityus serrulatus (Ts). It is a protein presenting 49 amino acid residues, three disulfide bridges, Mr 5534 Da and was classified as a new member of class (subfamily) 2 of the β-KTxs, the second one described for Ts scorpion. The β-KTx family is composed by two-domain peptides: N-terminal helical domain (NHD), with cytolytic activity, and a C-terminal CSαβ domain (CCD), with Kv blocking activity. The extensive electrophysiological screening (16 Kv channels and 5 Nav channels) showed that Ts19 Frag-II presents a specific and significant blocking effect on Kv1.2 (IC50 value of 544 ± 32 nM). However, no cytolytic activity was observed with this toxin. We conclude that the absence of 9 amino acid residues from the N-terminal sequence (compared to Ts19 Frag-I) is responsible for the absence of cytolytic activity. In order to prove this hypothesis, we synthesized the peptide with these 9 amino acid residues, called Ts19 Frag-III. As expected, Ts19 Frag-III showed to be cytolytic and did not block the Kv1.2 channel. The post-translational modifications of Ts19 and its fragments (I–III) are also discussed here. A mechanism of post-translational processing (post-splitting) is suggested to explain Ts19 fragments production. In addition to the discovery of this new toxin, this report provides further evidence for the existence of several compounds in the scorpion venom contributing to the diversity of the venom arsenal. 相似文献
20.
HWTX-III是从中国虎纹捕鸟蛛Ornithoctonus huwena粗毒中分离纯化到的一种昆虫神经多肽。通过应用全细胞膜片钳技术研究了HWTX-III对美洲蜚蠊Periplaneta americana神经细胞电压门控离子通道的影响。发现HWTX-III特异性地抑制美洲蜚蠊背侧不成对中间(dorsal unpaired median, DUM)神经细胞的电压门控钠通道(IC50≈1.106 μmol/L),而对电压门控钾通道没有明显的影响。HWTX-III通过一种新型的不同于其他蜘蛛毒素的机制抑制昆虫电压门控钠通道,它不影响通道的激活与失活动力学,也不明显地漂移稳态失活曲线。HWTX-III对昆虫神经细胞电压门控钠通道的特异性与新型作用机制为研究电压门控钠通道分子结构的多样性以及开发新的安全的杀虫剂提供有用的工具。 相似文献