Not so Dangerous After All? Venom Composition and Potency of the Pholcid (Daddy Long-Leg) Spider .

Pholcid spiders (Araneae: Pholcidae), officially "cellar spiders" but popularly known as "daddy long-legs," are renown for the potential of deadly toxic venom, even though venom composition and potency has never formally been studied. Here we detail the venom composition of male using proteomic analyses and venom-gland transcriptomes ("venomics"). We also analyze the venom's potency on insects, and assemble available evidence regarding mammalian toxicity.

Plectreurys tristis venome: A proteomic and transcriptomic analysis.

Spider venoms are complex cocktails rich in peptides, proteins and organic molecules that collectively act to immobilize prey. Venoms of the primitive hunting spider, Plectreurys tristis, have numerous neurotoxic peptides called "plectoxins" (PLTX), a unique acylpolyamine called bis(agmatine)oxalamide, and larger unidentified protein components. These spiders also have unconventional multi-lobed venom glands.

The alpha subunit of nitrile hydratase is sufficient for catalytic activity and post-translational modification.

Nitrile hydratases (NHases) possess a mononuclear iron or cobalt cofactor whose coordination environment includes rare post-translationally oxidized cysteine sulfenic and sulfinic acid ligands. This cofactor is located in the α-subunit at the interfacial active site of the heterodimeric enzyme. Unlike canonical NHases, toyocamycin nitrile hydratase (TNHase) from Streptomyces rimosus is a unique three-subunit member of this family involved in the biosynthesis of pyrrolopyrimidine antibiotics.

The identity of proteins associated with a small heat shock protein during heat stress in vivo indicates that these chaperones protect a wide range of cellular functions.

The small heat shock proteins (sHSPs) are a ubiquitous class of ATP-independent chaperones believed to prevent irreversible protein aggregation and to facilitate subsequent protein renaturation in cooperation with ATP-dependent chaperones. Although sHSP chaperone activity has been studied extensively in vitro, understanding the mechanism of sHSP function requires identification of proteins that are sHSP substrates in vivo. We have used both immunoprecipitation and affinity chromatography to recover 42 proteins that specifically interact with Synechocystis Hsp16.

Cleavage N-terminal to proline: analysis of a database of peptide tandem mass spectra.

Fragmentation at the Xxx-Pro bond was analyzed for a group of peptide mass spectra that were acquired in a Finnigan ion trap mass spectrometer and were generated from proteins digested by enzymes and identified by the Sequest algorithm. Cleavage with formation of a + b + y ions occurred more readily at the Xxx-Pro bond than at other locations in these peptides, and the importance of this cleavage varied by the identity of Xxx. The most abundant Xxx-Pro relative bond cleavage ratios were observed when Xxx was Val, His, Asp, Ile, and Leu, whereas the least abundant cleavage ratios occurred when Xxx was Gly or Pro.

Statistical characterization of ion trap tandem mass spectra from doubly charged tryptic peptides.

Collision-induced dissociation (CID) is a common ion activation technique used to energize mass-selected peptide ions during tandem mass spectrometry. Characteristic fragment ions form from the cleavage of amide bonds within a peptide undergoing CID, allowing the inference of its amino acid sequence. The statistical characterization of these fragment ions is essential for improving peptide identification algorithms and for understanding the complex reactions taking place during CID.