Project description:A study of cardiac troponin I evolution in mammals with high heart rates, including shrews, moles, and bats. With genomic, mRNA and protein level analyses we showed repeated loss of the N-terminal extension. Here, liquid chromatography with tandem mass spectrometry was used to verify cardiac troponin I (TNNI3) protein identity in ∼22 kDa bands from Pyrenean desman (Galemys pyrenaicus) and northern short-tailed shrew (Blarina brevicauda) hearts.
2024-07-19 | PXD048600 | Pride
Project description:Venomics of the northern short-tailed shrew, Blarina brevicauda
Project description:Venomous mammals are rare, and their venoms have not been characterized. We have purified and characterized the blarina toxin (BLTX), a lethal mammalian venom with a tissue kallikrein-like activity from the submaxillary and sublingual glands of the short-tailed shrew Blarina brevicauda. Mice administered BLTX i.p. developed irregular respiration, paralysis, and convulsions before dying. Based on the amino acid sequence of purified protein, we cloned the BLTX cDNA. It consists of a prosequence and an active form of 253 aa with a typical catalytic triad of serine proteases, with a high identity with tissue kallikreins. BLTX is an N-linked microheterogeneous glycoprotein with a unique insertion of 10 residues, L(106)TFFYKTFLG(115). BLTX converted kininogens to kinins, which may be one of the toxic pathogens, and had dilatory effects on the blood vessel walls. The acute toxicity and proteolytic activity of BLTX were strongly inhibited by aprotinin, a kallikrein inhibitor, suggesting that its toxicity is due to a kallikrein-like activity of the venom.
