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Kunitz-type Proteinase Inhibitor (kunitz-type + proteinase_inhibitor)
Selected AbstractsInsect silk contains both a Kunitz-type and a unique Kazal-type proteinase inhibitorFEBS JOURNAL, Issue 7 2001Xavier Nirmala Insect silk is made up of structural fibrous (fibroins) and sticky (sericins) proteins, and contains a few small peptides of hitherto unknown functions. We demonstrate that two of these peptides inhibit bacterial and fungal proteinases (subtilisin, proteinase K and pronase). These ,silk proteinase inhibitors' 1 and 2 (SPI 1 and 2) are produced in the middle section of the silk-secreting glands prior to cocoon spinning and their production is controlled at transcription level. The full length cDNA of pre-SPI 1 contains 443 nucleotides and encodes a peptide of 76 amino-acid residues, of which 20 make up a signal sequence. The mature SPI 1 (6056.7 Da, 56 residues) is a typical thermostable Kunitz-type proteinase inhibitor with Arg in P1 position. The cDNA of pre-SPI 2 consists of 260 nucleotides and yields a putative secretory peptide of 58 amino-acid residues. The functional SPI 2 (3993 Da, 36 residues) is a single-domain Kazal-type proteinase inhibitor with unique structural features: free segment of the N-terminus is reduced to a single amino-acid residue, lack of CysI and CysV precludes formation of the A-ring and provides increased flexibility to the C-ring, and absence of several residues around the normal position of CysV shortens and changes the , helix segment of the protein. The structure reveals that the length and arrangement of the B-ring, including exposure of the P1 residue, and the position of the C-terminus relative to the B-loop, are essential for the activity of the Kazal-type inhibitors. [source] The rediscovery and isolation of TFPIJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2003G. J. Broze Jr Summary., Tissue factor pathway inhibitor (TFPI) is a multivalent Kunitz-type proteinase inhibitor that produces factor (F)Xa-dependent feedback inhibition of the factor VIIa/tissue factor (FVIIa/TF) catalytic complex that is responsible for the initiation of coagulation. Since 1985, when Rapaport and colleagues reported that the lipoprotein fraction of plasma contained a FXa-dependent inhibitor of FVIIa/TF, myriad articles have established its biochemical structure, its mechanism of action, and its physiological importance. This brief personal account reviews historical studies that established the existence of the inhibitor and the events that led to its initial isolation. [source] Purification, crystallization and preliminary crystallographic studies of a Kunitz-type proteinase inhibitor from tamarind (Tamarindus indica) seedsACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2009Dipak N. Patil A Kunitz-type proteinase inhibitor has been purified from tamarind (Tamarindus indica) seeds. SDS,PAGE analysis of a purified sample showed a homogeneous band corresponding to a molecular weight of 21,kDa. The protein was identified as a Kunitz-type proteinase inhibitor based on N-terminal amino-acid sequence analysis. It was crystallized by the vapour-diffusion method using PEG 6000. The crystals belonged to the orthorhombic space group C2221, with unit-cell parameters a = 37.2, b = 77.1, c = 129.1,Å. Diffraction data were collected to a resolution of 2.7,Å. Preliminary crystallographic analysis indicated the presence of one proteinase inhibitor molecule in the asymmetric unit, with a solvent content of 44%. [source] | ||||||||||