A new role for PGRP-S (Tag7) in immune defense: lymphocyte migration is induced by a chemoattractant complex of Tag7 with Mts1

PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4⁺ and CD8⁺ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response.     

Restriction Endonuclease BspD6II,a New Thermophilic Isoschizomer of Eco57I

Russian Journal of Bioorganic Chemistry - From the Bacillus species D6 strain, the restriction endonuclease BspD6II has been isolated and characterized. It recognizes the asymmetric region...     

Nicking endonucleases

Nicking endonucleases are a new type of enzymes. Like restriction endonucleases, they recognize short specific DNA sequence and cleave DNA at a fixed position relatively to the recognition sequence. However, unlike restriction endonucleases, nicking endonucleases cleave only one predetermined DNA strand. Until recently, nicking endonucleases were suggested to be naturally mutated restriction endonucleases which had lost their ability to dimerize and as a result the ability to cleave the second strand. We have shown that nicking endonucleases are one of the subunits of heterodimeric restriction endonucleases. Mechanisms used by various restriction endonucleases for double-stranded cleavage, designing of artificial nicking endonucleases on the basis of restriction endonucleases, and application of nicking endonucleases in molecular biology are reviewed.     

Association between intracellular proteinase activities and the content of locomotor proteins in tissues of primary tumors and metastases of ovarian cancer

The capability for active movement in an extracellular matrix, wherein remodeling of the cytoskeleton by actin-binding proteins plays a significant role, may influence the metastatic potential of tumor cells. We studied the expression of actin-binding proteins and β-catenin in connection with proteasome and calpain functions in tissues of primary tumors and metastases of ovarian cancer. The chymotrypsin-like proteasome activity and calpain activity were shown to be significantly higher in ovarian cancer than in normal tissues. Furthermore, the activity of the proteasome and calpain were significantly higher in the peritoneal metastases in comparison with primary tumors. Correlation analysis showed the presence of a positive correlation between the activity of calpain and chymotrypsin-like proteasome activity (r = 0.82; p = 0.0005) in primary tumor tissue, whereas no such correlation was revealed in metastases. Contents of p45 Ser β-catenin and the actin-severing protein gelsolin were decreased in metastases relative to primary tumors. The level of the cofilin, functionally similar to gelsolin, was significantly higher in metastases compared to primary ovarian tumor tissue. In ovarian cancer, significant reduction in the number of an actin-monomer binder protein thymosin-β4 was observed in primary tumors and metastases as compared to normal tissues, but no significant differences between primary tumors and metastases were observed. In tissues of primary tumors, negative correlations were observed between the chymotrypsin-like activity of proteasomes and the amounts of p45 Ser β-catenin and protein Arp3, a member of the Arp2/3 complex. In metastasis, negative correlation was revealed between the activity of calpain and the content of Arp3, cofilin, and thymosin. The data obtained suggest that the mechanisms of proteolytic regulation of locomotor proteins in primary tumors and metastases in ovarian cancer are different.     

Investigation of site-specific DNA binding with nicking endonuclease Nt.BspD6I at single molecule level by atomic force microscopy

Nicking endonuclease Nt.BspD6I is a heterodimeric restriction endonuclease, one subunit of which exhibits specific nicking activity. It gets bound to double-stranded DNA and makes a break (nick) in one chain at a distance of 4 nucleotides from the binding site. In this work, for visualization of the specific binding and protein landing site, atomic force microscopy was used. In five minutes after incubation of DNA solution with nicking endonuclease, DNA molecules with associated proteins which located at the expected binding site and “shared” the DNA strand into two segments (approximately, 1/3 and 2/3 of length) were observed in the images. In addition, near the binding site the DNA molecule had a height corresponding to a single-stranded DNA molecule, which was in good agreement with single-stranded cleavage by nickase in the course of complex formation.     

The Role of Cysteine Residues in the Interaction of Nicking Endonuclease BspD6I with DNA

Molecular Biology - Nicking endonucleases (NEs) are a small, poorly studied family of restriction endonucleases. The enzymes recognize a target sequence in DNA, but catalyze the hydrolysis of only...     

AmylPepPred: Amyloidogenic Peptide Prediction tool

We present an efficient computational architecture designed using supervised machine learning model to predict amyloid fibril forming protein segments, named AmylPepPred. The proposed prediction model is based on bio-physio-chemical properties of primary sequences and auto-correlation function of their amino acid indices. AmylPepPred provides a user friendly web interface for the researchers to easily observe the fibril forming and non-fibril forming hexmers in a given protein sequence. We expect that this stratagem will be highly encouraging in discovering fibril forming regions in proteins thereby benefit in finding therapeutic agents that specifically aim these sequences for the inhibition and cure of amyloid illnesses.

Availability

AmylPepPred is available freely for academic use at www.zoommicro.in/amylpeppred