Activities and polymorphisms of MMP-2 and MMP-9, smoking,diabetes and risk of prostate cancer

Molecular Biology Reports - Matrix metalloproteinases (MMPs) are a group of zinc dependent enzymes that are involved in tumor cell invasion and metastasis. The role of MMP-2 and -9 genetic...     

Energy Allocation Changes in Overwintering Adults of the Common Pistachio Psylla, Agonoscena pistaciae Burckhardt & Lauterer (Hemiptera: Psyllidae)

The common pistachio psylla, Agonoscena pistaciae Burckhardt & Lauterer (Hemiptera: Psyllidae), is known as the key pest of pistachio orchards in Iran. This pest passes the winter as adults. In this study, energy allocation changes in relation to ambient temperature were investigated in field-collected adults by measuring total body sugar, trehalose, glucose, sorbitol, myoinositol, glycogen, lipid, and protein contents. Glycogen content decreased with decrease in ambient temperature. The decrease in glycogen content was proportional to the increase in total body sugar, trehalose, myoinositol, and sorbitol contents. In January, with mean ambient temperature of 5.4°C, glycogen content was at the lowest level, whereas total body sugar, trehalose, glucose, and sorbitol were at the highest level. Total body sugar, trehalose, myoinositol, and sorbitol contents increased as temperature decreased from 22.7°C in October to 5.4°C in January. In conclusion, low molecular weight carbohydrates and polyols may play a role in winter survival and adaptation to cold of the common pistachio psylla by providing the required cryoprotection. Also, overwintering adults of the common pistachio psylla may store energy in the form of lipid for later utilization during the overwintering.     

Kinetic analysis of the binding of hemopexin-like domain of gelatinase B cloned and expressed in Pichia pastoris to tissue inhibitor of metalloproteinases-1

The gelatinases are a subgroup of the matrix metalloproteinase family. The interaction of their C-terminal hemopexin-like domain with a tissue inhibitor of metalloproteinases (TIMP) is a major part of the regulatory mechanisms of gelatinases. To investigate the interaction of the hemopexin-like domain of gelatinase B (92-Pex) and TIMP-1, we expressed the individual domain in Pichia pastoris. The active refolded domain was purified by ion exchange chromatography and gel filtration. We investigated the formation of the 92-Pex/TIMP-1 complex by surface plasmon resonance (SPR). The dissociation constant Kd was calculated to be 0.86 nM. Analogous to the complex of the hemopexin-like domain of gelatinase A and TIMP-2 (Olson, M. W. et al., 1997), the binding curves of the 92-Pex/TIMP-1 complex were best fitted with a monophasic model.     

Identification of the active site of gelatinase B as the structural element sufficient for converting a protein to a metalloprotease

Gelatinase B is a member of the matrix metalloproteinase family that efficiently cleaves gelatin, elastin, and types V and X collagen. To understand the contribution of the active site of the enzyme (amino acid residues 373-456) in these activities, we studied catalytic properties of a fusion protein consisting of maltose binding protein and the active site region of gelatinase B. We found that addition of the active site of gelatinase B, which corresponds to 12% of the total protein molecule, to maltose binding protein is sufficient to endow the protein with the ability to cleave the peptide substrates Mca-PLGL(Dpa)AR-NH(2) and DNP-PLGLWA-(D)-R-NH(2). The fusion protein hydrolyzed the Mca-PLGL(Dpa)AR-NH(2) peptide with the same efficiency as that of the stromelysin, k(cat)/K(m) approximately 1.07 x 10(6) M(-)(1) h(-)(1). The fusion protein, however, was not able to degrade the large substrate, gelatin. Inhibition of the activity of the protein by EDTA suggested that its activity was metal dependent. ESR analyses indicated that the fusion protein bound one molecule of Zn(2+). In addition, Z-Pro-Leu-Gly-hydroxamate and TIMP-1 inhibited the activity of the protein, suggesting that the structure of the active site of the fusion protein is similar to that of the other metalloproteinases. These data provide fundamental information about the structural elements required for transforming a protein to a metalloprotease.     

Unexpected crucial role of residue 272 in substrate specificity of fibroblast collagenase

Degradation of type I collagen by collagenases is an important part of extracellular remodeling. To understand the role of the hinge region of fibroblast collagenase in its collagenolytic activity, we individually substituted the 10 conserved amino acid residues at positions 264, 266, 268, 296, 272, 277, 284, 289, 307, and 313 in this region of the enzyme by their corresponding residues in MMP-3, a noncollagenolytic matrix metalloproteinase. The general proteolytic and triple helicase activities of all of the enzymes were determined, and their abilities to bind to type I collagen were assessed. Among the mutants, only G272D mutant enzyme exhibited a significant change in type I collagenolysis. The alteration of the Gly(272) to Asp reduced the collagenolytic activity of the enzyme to 13% without affecting its general proteolytic activity, substrate specificity, or the collagen binding ability. The catalytic efficiency of the G272D mutant for the triple helical peptide substrate [C(6)-(GP- Hyp)(4)GPL(Mca)GPQGLRGQL(DPN)GVR(GP-HYP)(4)-NH(2)](3) and the peptide substrate Mca-PLGL(Dpa)AR-NH(2) and its dissociation constant for the triple helical collagen were similar to that of the wild type enzyme, indicating that the presence of this residue in fibroblast collagenase is particularly important for the efficient cleavage of type I collagen. Gly(272) is evidently responsible for the hinge-bending motion that is essential for allowing the COOH-terminal domain to present the collagen to the active site.     

Time‐Dependent Morphology Evolution of Solution‐Processed Small Molecule Solar Cells during Solvent Vapor Annealing

Morphological modification using solvent vapor annealing (SVA) provides a simple and widely used fabrication option for improving the power conversion efficiencies of solution‐processed bulk heterojunction (BHJ) small molecule solar cells. Previous reports on SVA have shown that this strategy influences the degree of donor/acceptor phase separation and also improves molecular donor ordering. A blend composed of a dithienopyrrole containing oligothiophene as donor (named UU07) and [6,6]‐phenyl‐C61‐butyric acid methyl ester as acceptor is investigated with respect to SVA treatment to explore the dynamics of the BHJ evolution as a function of annealing time. A systematic study of the time dependence of morphology evolution clarifies the fundamental mechanisms behind SVA and builds the structure–property relation to the related device performance. The following two‐stage mechanism is identified: Initially, as SVA time increases, donor crystallinity is improved, along with enhanced domain purity resulting in improved charge transport properties and reduced recombination losses. However, further extending SVA time results in domains that are too large and a few large donor crystallites, depleting donor component in the mixed domain. Moreover, the larger domain microstructure suffers from enhanced recombination and overall lower bulk mobility. This not only reveals the importance of precisely controlling SVA time on gaining morphological control, but also provides a path toward rational optimization of device performance.     

Fatty Acid Patterns of Seeds of Some Salvia Species from Iran – A Chemotaxonomic Approach

In this study, the seed oil content and fatty acid (FA) profile of 21 populations from 16 wild Salvia species of Iran were analyzed by GC. Patterns of chemical variations of the oils among species were identified via numerical analyses and also the taxonomic status of the infrageneric grouping was outlined in the genus. Salvia species were scored based on the contents of main FAs using principal coordinate analysis (PCO). The results showed that the total oil content in the seeds varied significantly, and ranged from 6.68 to 38.53% dry weight. α‐Linolenic (18:3ω3, 1.69 – 53.56%), linoleic (18:2ω6, 13.04 – 60.64%), oleic (18:1ω9, 6.15 – 27.06%), palmitic (16:0, 3.77 – 9.27%), and stearic (18:0, 1.78 – 3.05%) acid were identified as five major FAs in the oils. The amount of ω‐3 and ω‐6 FAs ranged between 1.90 – 53.80% and 13.46 – 60.83% of total FAs in the seed oils, respectively. The results confirmed that FA profiles were distinctive among the species and that they can be used as chemotaxonomic markers. The discrimination of Salvia species according to their botanical classification at intersectional level was supported. In general, seed oils of Salvia species were rich sources of polyunsaturated FAs, except in linoleic and α‐linolenic acid, and may be valuable for food and pharmaceutical industries.