Johanna Kallio

Crystal structures of hydrophobin HFBII in the presence of detergent implicate the formation of fibrils and monolayer films

Hydrophobins are small, amphiphilic proteins secreted by filamentous fungi. Their functionality arises from a patch of hydrophobic residues on the protein surface. Spontaneous self-assembly of hydrophobins leads to the formation of an amphiphilic layer that remarkably reduces the surface tension of water. We have determined by x-ray diffraction two new crystal structures of Trichoderma reesei hydrophobin HFBII in the presence of a detergent. The monoclinic crystal structure (2.2Å resolution, R = 22, Rfree = 28) is composed of layers of hydrophobin molecules where the hydrophobic surface areas of the molecules are aligned within the layer. Viewed perpendicular to the aligned hydrophobic surface areas, the molecules in the layer pack together to form six-membered rings, thus leaving small pores in the layer. Similar packing has been observed in the atomic force microscopy images of the self-assembled layers of class II hydrophobin, indicating that the crystal structure resembles that of natural hydrophobin film. The orthorhombic crystal structure (1.0Å resolution, R = 13, Rfree = 15) is composed of fiber-like arrays of protein molecules. Rodlet structures have been observed on amphiphilic layers formed by class I hydrophobins; fibrils of class II hydrophobins appear by vigorous shaking. We propose that the structure of the fibrils and/or rodlets is similar to that observed in the crystal structure.

Crystal structures of Trichoderma reesei β-galactosidase reveal conformational changes in the active site

We have determined the crystal structure of Trichoderma reesei (Hypocrea jecorina) β-galactosidase (Tr-β-gal) at a 1.2Å resolution and its complex structures with galactose, IPTG and PETG at 1.5, 1.75 and 1.4Å resolutions, respectively. Tr-β-gal is a potential enzyme for lactose hydrolysis in the dairy industry and belongs to family 35 of the glycoside hydrolases (GH-35). The high resolution crystal structures of this six-domain enzyme revealed interesting features about the structure of Tr-β-gal. We discovered conformational changes in the two loop regions in the active site, implicating a conformational selection-mechanism for the enzyme. In addition, the Glu200, an acid/base catalyst showed two different conformations which undoubtedly affect the pK(a) value of this residue and the catalytic mechanism. The electron density showed extensive glycosylation, suggesting a structure stabilizing role for glycans. The longest glycan showed an electron density that extends to the eighth monosaccharide unit in the extended chain. The Tr-β-gal structure also showed a well-ordered structure for a unique octaserine motif on the surface loop of the fifth domain.

Social workers’ perceptions of the causes of poverty in the Nordic countries:

Street-level bureaucrats have been given an increasing role in the implementation of policies aimed at the poor. The article analyses: (1) how social workers in the Nordic countries explain the causes of poverty and whether there are variations between countries in social workers’ perceptions; and (2) the nature of the impact, if any, of various individual- and municipal-level factors on social workers’ perceptions of the causes of poverty. Survey data gathered from social workers in four countries are analysed and combined with data from the municipalities in which the respondents work. The results illustrate that social workers display a surprisingly large variation in perceptions: there are differences between countries and also differences related to individual-level factors, while municipality-level factors do not appear to influence the perceptions of social workers in an obvious way.

Specific hybridization probes for mouse α2(IX) and α1(X) collagen mRNAs

We have used polymerase chain reaction (PCR) technology and available cross-species sequence information to construct cDNA probes for mouse α2(IX) and α1(X) collagen transcripts. Sequencing confirmed the identification of the clones. Northern analysis proved sufficient divergence of the cloned sequences from other collagen transcripts: specific etection of the mouse 2.9 kb α2(IX) and 3.3 kb α1(X) collagen mRNAs was seen under normal hybridization and washing conditions.

The contribution of polystyrene nanospheres towards the crystallization of proteins.

Background Protein crystallization is a slow process of trial and error and limits the amount of solved protein structures. Search of a universal heterogeneous nucleant is an effort to facilitate crystallizability of proteins. Methodology The effect of polystyrene nanospheres on protein crystallization were tested with three commercial proteins: lysozyme, xylanase, xylose isomerase, and with five research target proteins: hydrophobins HFBI and HFBII, laccase, sarcosine dimethylglycine N-methyltransferase (SDMT), and anti-testosterone Fab fragment 5F2. The use of nanospheres both in screening and as an additive for known crystallization conditions was studied. In screening, the addition of an aqueous solution of nanosphere to the crystallization drop had a significant positive effect on crystallization success in comparison to the control screen. As an additive in hydrophobin crystallization, the nanospheres altered the crystal packing, most likely due to the amphiphilic nature of hydrophobins. In the case of laccase, nanospheres could be used as an alternative for streak-seeding, which insofar had remained the only technique to produce high-diffracting crystals. With methyltransferase SDMT the nanospheres, used also as an additive, produced fewer, larger crystals in less time. Nanospheres, combined with the streak-seeding method, produced single 5F2 Fab crystals in shorter equilibration times. Conclusions All in all, the use of nanospheres in protein crystallization proved to be beneficial, both when screening new crystallization conditions to promote nucleation and when used as an additive to produce better quality crystals, faster. The polystyrene nanospheres are easy to use, commercially available and close to being inert, as even with amphiphilic proteins only the crystal packing is altered and the nanospheres do not interfere with the structure and function of the protein.

Who Blames the Poor

ABSTRACT The article analyses the support for and determinants of individualistic explanations of poverty among Europeans. The analyses are conducted using multilevel logistic regression models. Findings suggest that the level of support for the individualistic explanation of poverty varies between European nations. Hence, the results contradict the analysis of Alesina and Glaeser (2004, Fighting Poverty in the US and Europe. A World of Difference), which gives us a very homogenous picture of European attitudes towards the poor. Among the determinants of poverty perceptions, welfare regime, short-term economic growth and social expenditures as well as individual-level demographic factors, perceived economic hardship, political affiliation and egalitarian values are associated with the individualistic attribution for poverty. In general, the findings hold critical implications for future research to develop further dynamic measurement of contextual level explanatory factors.

Characterization and crystallization of a recombinant IgE Fab fragment in complex with the bovine β-lactoglobulin allergen

A D1 Fab fragment containing the allergen-binding variable domains of the IgE antibody was characterized by ESI FT-ICR mass spectrometry and crystallized with bovine beta-lactoglobulin (BLG) using the hanging-drop vapour-diffusion method at 293 K. X-ray data suitable for structure determination were collected to 2.8 A resolution using synchrotron radiation. The crystal belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 67.0, b = 100.6, c = 168.1 A. The three-dimensional structure of the D1 Fab fragment-BLG complex will provide the first insight into IgE antibody-allergen interactions at the molecular level.

Parental Resources, Sibship Size, and Educational Performance in 20 Countries Evidence for the Compensation Model

We study whether having several siblings decreases the level of educational performance of adolescents and whether this phenomenon can be compensated by other factors such as the economic or cultural resources of the parents. Based on this compensation model, parental resources should be associated with children’s educational attainments more strongly in families with a higher rather than a lower number of children. We analyzed the Program for International Student Assessment (PISA) data from 20 Western countries and found that better family wealth, an increased level of parental education, and a higher parental occupational status were associated with increased educational attainments more strongly among 15-year-old children who have siblings than among children without siblings. The same effect was not found in the case of family cultural possessions. Although parental resources may matter more in larger families than in smaller families, some types of resources are more important than others regarding compensation.

Crystallization and preliminary diffraction analysis of a β-galactosidase from Trichoderma reesei

An extracellular beta-galactosidase from Trichoderma reesei was crystallized from sodium cacodylate buffer using polyethylene glycol (PEG) as a precipant. Crystals grown by homogenous streak-seeding belonged to space group P1, with unit-cell parameters a = 67.3, b = 69.1, c = 81.5 A, alpha = 109.1, beta = 97.3, gamma = 114.5 degrees . The crystals diffracted to 1.8 A resolution using a rotating-anode generator and to 1.2 A resolution using a synchrotron source. On the basis of the Matthews coefficient (V(M) = 3.16 A(3) Da(-1)), one molecule is estimated to be present in the asymmetric unit. The aim of the determination of the crystal structure is to increase the understanding of this industrially significant enzyme.

Street-level bureaucrats’ attitudes towards the Finnish labour market allowance

Purpose – The purpose of this paper is to examine the attitudes of street-level bureaucrats from different agencies and sectors of the Finnish welfare state, namely municipal social workers, diaconal workers of the Lutheran church, benefit officials of the Social Security Institution and officials of private unemployment funds. Design/methodology/approach – The authors are interested in the following questions: What are the attitudes of street-level bureaucrats towards the labour market allowance? What is the impact of individual characteristics? The study utilised the unique national survey data of different groups of street-level bureaucrats from the year 2011 (total N=2,313). The dependent variables focus on legitimacy of the basic level of labour market allowance and sanction policies. Analyses are built around five independent variables which measure professional, personal interest and ideological factors. Findings – There are differences both between and within groups of Finnish street-level bureauc...