Conformations of three series of peptides: H-Trp-(Pro)n-Tyr-OH (n = 1-5), H-Trp-(Pro)n-Met-OH (n = 1-3) and H-Tyr-(Pro)n-Met-OH (n = 1-3), used as models in studies on long range electron transfer through protein matrix, were investigated by CD spectroscopy in aqueous solution at pH 5.2 in the temperature range of 10°C-90°C. CD spectra of their component N- and C-terminal dipeptide and oligoproline fragments were also measured under similar conditions. In interpretation of the spectra the cis <-> trans equilibrium about X-Pro bonds was taken into account and CD spectra of Trp-Pro and Tyr-Pro chromophores in trans and cis configuration of the peptide bond were evaluated. The spectra of n = 3-5 peptides from the first series and those with n = 2-3 from the other two series exhibit a strong negative band in the 202-207 nm region, the strength of which is proportional to the number of Pro residues in the (Pro)n bridge, and characterized by a large temperature decrement. In view of close similarity between characteristics of this band and the 206 nm band of aqueous oligoproline peptides = 3), known to attain a left handed helical conformation similar to that of 31 helix of the all-trans poly-L-proline II, this band was attributed to a conformation of the latter type. H-Trp-(Pro)2-Tyr-OH does not form this conformation due to sterical interaction between the two bulky aromatic side chains. Conclusions drawn from analysis of the CD spectra are supported by 1H and C13 NMR data reported elsewhere (Poznański et al., 1993, Biopolymers 33,781-795).
Fluorescence resonance energy transfer (FRET) is a technique widely used in studies of interchromophoric distances in biomolecules such as peptides, proteins and nucleic acids. FRET is especially useful in determination of conformational changes caused by a solvent, presence of denaturing agents, diffusion and other external factors. Precision of interchromophoric distances obtained using the FRET technique is comparable with that of low-resolution X-ray diffraction and NMR data. Comparison of FRET results with the crystal structure for several proteins is reviewed. Moreover, the effect of the orientation factor K2 value on FRET results and determinants of k2 are discussed.
The criteria for choosing a companion dog. What criteria do people follow in selecting a dog in Poland? By means of a diagnostic survey a study was carried out examining the criteria for selecting a companion dog. The survey was filled out by 424 dog owners (in Poland), representing various ages and education. An analysis of the results allowed to divide the surveyed community into five clusters. The respondents from the 1st cluster preferred pedigree dogs. They regarded the most important criteria of dog selection to be parentage (0.809), size (0.652) and temperament(0.478). The 2nd cluster included people having a good contact with dogs and preferring a specific type of dog temperament. They most highly regarded the temperamentof the dog (1.000) and its appearance (0.693). The 3rd cluster included altruists, for whom none of the analyzed criteria of selection were important. For them the most important criteria of dog selection was the temperamentof the animal (0.977), less important were sex (0.593), parentage (0.558) and the utility purpose (0.453), whereas age and external appearance were completely irrelevant. The respondents in the 4th cluster (people preferring work and physical activity with the dog) differed from the others by having the highest assessment of the dog's utility purpose (0.906). Their utilitarian attitude towards dog selection confirms regarding temperamentas second in the hierarchy of criteria (0.750) and size as the third (0.547). The least traits associated with the utilitarian side of the dog were shown by respondents from the 5th cluster (average dog owners). They regarded the following criteria to be most important: size (0.688), age and appearance (0.656) and sex (0.563).
The lifetime distribution calculations were applied to study the influence of configuration of amino-acid residues in positions 2 and 3 on changes in conformation of the peptide chain of cyclic analogues of enkephalins containing a fluorescence energy donor and acceptor in different solvents. In all the solvents studied the lifetime distributions were bimodal. This testified to the presence of two families of conformations. In this paper the relationship between the population of each conformation and configuration of the residues in position 2 and 3, and the solvent used is discussed.
Classification of slaughter animals in EUROP system is obligatory for all EU countries. Visual assessment of beef carcasses determines the level of muscle and fat in scales from E to P and from 1 to 5. At the same time beef carcass is classified into one of five categories of cattle for slaughter from A to E. Visual assessment is not fully objective and is fraught with classifier error, which has an impact on the final assessment of the carcass. 2689 beef carcasses were classified in different categories for slaughter. Assessments were performed by three classifiers independently and in the same conditions in the slaughter line. Based on the results of evaluations of beef carcasses were performed statistical analysis. The average value for the conformation was class O, which accounted for 52.66% of all beef carcasses and at a comparable level fat class 2 and 3 – 39.54%, 32.54% respectively, which is characterized by a low content of meat and average fat content in carcase. CV (coefficient of variation) for the SE (standard deviation) in the conformation class was around 3% for the three categories slaughter A, B and E, and D was 2.16%. For the fat class regardless of the category slaughter CV for the SE was 3 times larger. The results suggest that visual assessment of beef carcasses is not objective and is fraught with error evaluator.
Lifetime distribution analysis were performed to study the influence of Leu configuration in position 5 on changes of the peptide chain of cyclic analogues of enkephalins containing a fluorescence donor and acceptor in different solvents. The configuration change of Leu5 in all the analogues of enkephalins studied which contain donor-acceptor pairs has no apparent influence on Trp lifetime distributions. In contrast, there is a significant solvent effect on the shape of lifetime distribution.
The biologically active conformation of thymopoietin, based on X-ray data reported for discontinuous thymopoietin-like motif of G-actin, is proposed. The conformation is compared with that resulting from the prediction made by the method of Chou & Fasman (Annu. Rev. Biochem. 47, 251-276, 1978) and Rost & Sander (Methods Enzymol. 266, 525-539, 1996).
The research material consisted of 101 primiparous cows born from Chaloraise sires. Cows were divided into four genotype groups: 1) pure-bred Charolaise, 2) crossbreds with 75% Charolaise and 25% Black-and-White, 3) crossbreds with 50% Charolaise and 50% Black-and- -White, 4) crossbreds with 50% Charolaise and 50% Simmental.An analysis of the body weight of primiparous cows and calves at weaning was performed. The measurements of the height at withers, hip height and chest girth were taken and the assessment of conformation, size and production traits was carried out. The crossbred cows obtained results similar to or somewhat worse than those for the pure-bred Charolaise cows. The obtained results indicate that cows crossbred with Black-and-White breed are a very good material for the production of beef calves with the fattening traits similar to those of the beef breed used for absorptive crossing or the crossbred cows of pure beef breeds.
Bacillus licheniformis α-amylase (BLA) was chemically modified using 100-fold molar excess of succinic anhydride over protein or 0.66 M potassium cyanate to obtain 42 % succinylated and 81 % carbamylated BLAs. Size and charge homogeneity of modified preparations was established by Sephacryl S-200 HR gel chromatography and polyacrylamide gel electrophoresis. Conformational alteration in these preparations was evident by the larger Stokes radii (3.40 nm for carbamylated and 3.34 nm for succinylated BLAs) compared to 2.43 nm obtained for native BLA. Urea denaturation results using mean residue ellipticity (MRE) as a probe also showed conformational destabilization based on the early start of transition as well as ΔGDH2O values obtained for both modified derivatives and Ca-depleted BLA. Decrease in ΔGDH2O value from 5,930 cal/mol (for native BLA) to 3,957 cal/mol (for succinylated BLA), 3,336 cal/mol (for carbamylated BLA) and 3,430 cal/mol for Ca-depleted BLA suggested reduced conformational stability upon modification of amino groups of BLA or depletion of calcium. Since both succinylation and carbamylation reactions abolish the positive charge on amino groups (both α- and ε- amino), the decrease in conformational stability can be ascribed to the disruption of salt bridges present in the protein which might have released the intrinsic calcium from its binding site.
The aim of the studies was to determine the effects of media with composts, based on sewage sludge and potato pulp, on the growth and conformation of the cultivar 'Butterfly Yellow with Blotch'. In the experiment 14 potting media, including 12 media made of 4 composts, were tested. The percentage of compost mixed with sphagnum peat was 25%, 50% and 75%. The components of particular composts were as follows: I - municipal sewage sludge 70% and straw 30%; II - municipal sewage sludge 70% and sawdust 30%; III - municipal sewage sludge 35%, potato pulp 35% and straw 30%; IV - municipal sewage sludge 35%, potato pulp 35% and sawdust 30%. Two control potting media were used: 1 - sphagnum peat with Osmocote Exact Lo-Start at the dose 5 g×dm⁻³, and 2 - sphagnum peat with Azofoska at the dose 2.5 g×dm⁻³. There was no top-dressing during cultivation. The potting media used for pansy cultivation were rich in essential nutrients and in certain media macroelement content exceeded the limits recommended for the species with great nutrient requirements. The effects of the media on the growth, conformation and foliage of pansies depended on compost composition and its pecentage in a medium. The composts used for the media were found to be suitable for pansy cultivation. Despite smaller leaf rosettes in comparison with control plants, the pansies from compost media grew well and showed no disease symptoms.
The solution structure and thermal stability of human prostatic acid phosphatase (hPAP) in the absence and in the presence of tartaric acid were studied by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The temperature dependence of the infrared spectrum and DSC scans indicate that hPAP undergoes thermal unfolding at a temperature between 49.5 and 52.5°C. Binding of tartaric acid does not lead to major changes in the secondary structure of hPAP, however, hPAP with bound tartaric acid shows a significantly increased thermal stability. These results helped to better understand the mechanism of hPAP unfolding at the elevated temperature.