| isolation and characterization of a t-superfamily conotoxin from conus litteratus with targeting tetrodotoxin-sensitive sodium channels. | a t-1-conotoxin, lt5d, was purified and characterized from the venom of vermivorous hunting cone snails conus litteratus. the complete amino acid sequence of lt5d (dccpakllccnp) has been determined by edman degradation. with two disulfide bonds, the calculated average mass is 1274.57 da, which is confirmed by maldi-tof mass spectrometry (average mass 1274.8778). under whole cell patch-clamp mode, lt5d inhibits tetrodotoxin-sensitive sodium currents on adult rat dorsal root ganglion neurons, but ... | 2007 | 17961831 |
| identification of a novel m-superfamily conotoxin with the ability to enhance tetrodotoxin sensitive sodium currents. | in this work, a novel m-superfamily conotoxin, designated lt3a, was purified from the crude venom of conus litteratus. combined with peptide sequencing, maldi-tof mass spectrometry and cdna cloning techniques, the amino acid sequence of lt3a was supposed to be dgammaccgamma oqwcdgacdccs, where o is hydroxyproline and gamma is carboxyglutamate. the cys framework of lt3a (-cc-c-c-cc-) is similar to that of psi-, mu-, kappam-conotoxins, which are representatives of m-conotoxins. peptide lt3a is cat ... | 2009 | 19562324 |
| atypical alpha-conotoxin ltia from conus litteratus targets a novel microsite of the alpha3beta2 nicotinic receptor. | different nicotinic acetylcholine receptor (nachr) subtypes are implicated in learning, pain sensation, and disease states, including parkinson disease and nicotine addiction. alpha-conotoxins are among the most selective nachr ligands. mechanistic insights into the structure, function, and receptor interaction of alpha-conotoxins may serve as a platform for development of new therapies. previously characterized alpha-conotoxins have a highly conserved ser-xaa-pro motif that is crucial for poten ... | 2010 | 20145249 |
| soluble expression, purification and functional identification of a disulfide-rich conotoxin derived from conus litteratus. | conotoxins are a diverse array of small peptides mostly with multiple disulfide bridges. these peptides become an increasing significant source of neuro-pharmacological probes and drugs as a result of the high selectivity for ion channels and receptors. usually, the analogue of natural conotoxins is produced by means of chemical synthesis. here, we present a simple and fast strategy of producing disulfide-rich conotoxins via recombinant expression. by fused with thioredoxin and his tag, a novel ... | 2007 | 17069917 |
| discovery of a novel class of conotoxin from conus litteratus, lt14a, with a unique cysteine pattern. | conus litteratus is a worm-hunting cone snail with a highly sophisticated neuropharmacological defense strategy using small peptides in its venom. by analyzing different clones in the cdna library of venom ducts from c. litteratus, we identified the peptide lt14a which displays a characteristic signal peptide sequence in its precursor and a unique arrangement of cys residues (-c-c-c-c-) in its mature peptide region. rt-pcr analysis suggested that lt14a is abundantly expressed throughout the whol ... | 2006 | 16797781 |
| identification and characterization of a novel o-superfamily conotoxin from conus litteratus. | a novel conotoxin named lt6c, an o-superfamily conotoxin, was identified from the cdna library of venom duct of conus litteratus. the full-length cdna contains an open reading frame encoding a predicted 22-residue signal peptide, a 22-residue proregion and a mature peptide of 28 amino acids. the signal peptide sequence of lt6c is highly conserved in o-superfamily conotoxins and the mature peptide consists of six cysteines arranged in the pattern of c-c-cc-c-c that is defined the o-superfamily of ... | 2008 | 18523965 |
| structure-function relationship of conotoxin lt14a, a potential analgesic with low cytotoxicity. | a novel conotoxin lt14a containing 13 amino acid residues with an amidated c-terminus derived from conus litteratus, belongs to c-c-c-c cysteine pattern. as the smallest peptide of conotoxin framework 14, lt14a could inhibit nicotinic acetylcholine receptor and suppress pain. to elucidate structure-function relationship, we determine the solution structure by nmr and find that lt14a comprises a short duple β-strand region and β-turn motif. an analog [k7a]-lt14a of ala substitution for lys in pos ... | 2010 | 21126549 |
| soluble expression and sodium channel activity of lt16a, a novel framework xvi conotoxin from the m-superfamily. | a peptide toxin, lt16a, from the venom of the worm-hunting conus litteratus, shares the typical signal peptide sequences of m-superfamily conotoxins, which usually contain six cysteine residues that are arranged in a cc-c-c-cc pattern. interestingly, lt16a comprises 21 amino acid residues in its mature region and has a cysteine framework xvi, which is arranged in a c-c-cc pattern. the coding region of lt16a was cloned into the ptrx vector and the fusion protein was overexpressed in escherichia c ... | 2015 | 25600641 |
| soluble expression, purification and functional identification of the framework xv conotoxins derived from different conus species. | the conotoxin cysteine framework xv (-c-c-cc-c-c-c-c-), which was named lt15a, was firstly identified from the cdna library of conus litteratus. after that, 18 new framework xv conotoxin sequences were cloned from nine conus species. like other conopeptides, the xv-conotoxins have the conserved signal peptide and propeptide, and there are also some conserved residues in their mature peptide. all the framework xv conotoxins were apparently converged into two branches, because of the indel and poi ... | 2014 | 24703966 |
| identification of novel i-superfamily conopeptides from several clades of conus species found in the south china sea. | the i-superfamily of conus peptides represents a new class of peptides with four disulfide bridges (-c-c-cc-cc-c-c-) that falls into three (i1, i2 and i3) categories according to the different signal peptide sequences. the i-superfamily has received increasing attention because it targets k+ ion channels, a function that is relatively rare in conotoxins. herein we report 11 novel i-superfamily conotoxins from the venom ducts of five cone snails (conus eburneus, conus imperialis, conus vitulinus, ... | 2009 | 19595726 |
| identification of a novel class of conotoxins defined as v-conotoxins with a unique cysteine pattern and signal peptide sequence. | cone snails are predatory gastropod mollusks distributed in all tropical marine habitats with a highly sophisticated defense strategy using small peptides in their venoms. here, we report the discovery and initial characterization of the v-superfamily conotoxins. a novel conotoxin vi15a was purified from the venom of a worm-hunting species conus virgo. the sequence of vi15a was determined to have a unique arrangement of cysteine residues (c-c-cc-c-c-c-c), which defines the new v-superfamily cono ... | 2008 | 18304695 |
| identification and molecular diversity of t-superfamily conotoxins from conus lividus and conus litteratus. | the t-superfamily conotoxins comprise a large and diverse group of biologically active peptides and are widely distributed in venom ducts of all major feeding types of conus. six novel t-superfamily peptides from the two worm-hunting cone snail species of conus lividus andconus. litteratus native to hainan were identified and determined to share a common signal sequence as well as a conserved arrangement of cysteine residues (cc-cc). the predicted mature peptides consist of 11-15 amino acids onl ... | 2006 | 16999774 |
| novel alpha-conotoxins identified by gene sequencing from cone snails native to hainan, and their sequence diversity. | conotoxins (ctx) from the venom of marine cone snails (genus conus) represent large families of proteins, which show a similar precursor organization with surprisingly conserved signal sequence of the precursor peptides, but highly diverse pharmacological activities. by using the conserved sequences found within the genes that encode the alpha-conotoxin precursors, a technique based on rt-pcr was used to identify, respectively, two novel peptides (lic22, led2) from the two worm-hunting conus spe ... | 2006 | 16981242 |
| diversity and evolution of conotoxins based on gene expression profiling of conus litteratus. | cone snails are attracting increasing scientific attention due to their unprecedented diversity of invaluable channel-targeted peptides. as arguably the largest and most successful evolutionary genus of invertebrates, conus also may become the model system to study the evolution of multigene families and biodiversity. here, a set of 897 expressed sequence tags (ests) derived from a conus litteratus venom duct was analyzed to illuminate the diversity and evolution mechanism of conotoxins. nearly ... | 2006 | 16908117 |
| pharmacological characterization of conotoxin lt14a as a potent non-addictive analgesic. | conotoxin lt14a is a small peptide consisting of 13 amino acids. it was originally identified from the cdna of conus litteratus in the south china sea. previous reports showed lt14a exhibited antinociceptive activity using a hot plate-induced pain mouse model and acted as an antagonist of neuronal nicotinic acetylcholine receptors. we confirmed that conotoxin lt14a administration resulted in antinociception activity using a mouse inflammatory pain model and a rat model of mechanically-induced pa ... | 2015 | 25617597 |
| trace metal pollution and its influence on the community structure of soft bottom molluscs in intertidal areas of the dar es salaam coast, tanzania. | the influence of trace metal pollution on the community structure of soft bottom molluscs was investigated in intertidal areas of the dar es salaam coast. significant enrichment of as, mn, mo, sb, and zn in sediments was recorded. redundancy analysis indicated that trace metal pollution contributed 68% of the variation in community structure. monte carlo permutation test showed that as and sb contributed significantly to variation in species composition. t-value biplots and van dobben circles sh ... | 2012 | 22248646 |
| cdna cloning of conotoxins with framework xii from several conus species. | in our efforts for cloning novel i(2)-superfamily conotoxins using the signal peptide sequence, we identified a novel conotoxin lt12.4 from conus litteratus. this gene has a framework xii (-c-c-c-c-cc-c-c-), which is distinct from the cysteine pattern i(2)-superfamily conotoxin (-c-c-cc-cc-c-c-). subsequently, we found the signal peptide sequence of lt12.4 by 5'-race. using this new sequence, we identified another five novel conotoxins with this cysteine pattern from four conus species (conus eb ... | 2010 | 20732855 |