| 131. |
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| 132. |
- Hammarström, Per, 1960-
(författare)
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Omvändelseberättelser, judemission och svensk lågkyrklighet runt sekelskiftet 1900
- 2012. - 1
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Ingår i: Från legofolk till stadsfolk. - Härnösand : Institutionen för Humaniora. - 9789186694937 ; , s. 137-153
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Lågkyrkliga Svenska Israelsmissionen, grundades som en inomkyrklig rörelse på 1870-talet med syftet att bedriva evangeliskt och socialt arbete bland judar i Sverige och utomlands. Inte minst genom det proselythem som grundades i Stockholm kom judar i kontakt med föreningen, något som emellanåt ledde fram till att judar konverterade till kristendomen. Flertalet av de omvända var judiska ynglingar med rötterna i Östeuropa och det hände att Israelsmissionen anställde de nyomvända som resepredikanter och judemissionärer. I religiösa självbiografier har de skildrat sin judiska uppväxt i Östeuropa, invandringen till Sverige, religiösa kriser, omvändelse, dop och missionärsverksamhet. I denna text diskuteras sex sådana religiösa omvändelseberättelser, publicerade perioden 1888–1927, dels den religiösa och sociala kontext i vilken berättelserna formades, dels de skäl som legat bakom omvändelserna. Undersökningen visar på en starkt antijudisk diskurs inom Israelsmissionen som konvertiterna övertog och reproducerade i sina texter, men också en romantiserad syn på drag inom judendomen. De självbiografiska texterna skildrar livskriser som en följd av uppbrott och invandring och behovet av tillhörighet i en ny omgivning, något som kan ses som förklaringar till konversionerna.
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| 133. |
- Hammarström, Per, et al.
(författare)
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Porcine prion protein amyloid
- 2015
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Ingår i: Prion. - : Taylor andamp; Francis: STM, Behavioural Science and Public Health Titles. - 1933-6896 .- 1933-690X. ; 9:4, s. 266-277
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Tidskriftsartikel (refereegranskat)abstract
- Mammalian prions are composed of misfolded aggregated prion protein (PrP) with amyloid-like features. Prions are zoonotic disease agents that infect a wide variety of mammalian species including humans. Mammals and by-products thereof which are frequently encountered in daily life are most important for human health. It is established that bovine prions (BSE) can infect humans while there is no such evidence for any other prion susceptible species in the human food chain (sheep, goat, elk, deer) and largely prion resistant species (pig) or susceptible and resistant pets (cat and dogs, respectively). PrPs from these species have been characterized using biochemistry, biophysics and neurobiology. Recently we studied PrPs from several mammals in vitro and found evidence for generic amyloidogenicity as well as cross-seeding fibril formation activity of all PrPs on the human PrP sequence regardless if the original species was resistant or susceptible to prion disease. Porcine PrP amyloidogenicity was among the studied. Experimentally inoculated pigs as well as transgenic mouse lines overexpressing porcine PrP have, in the past, been used to investigate the possibility of prion transmission in pigs. The pig is a species with extraordinarily wide use within human daily life with over a billion pigs harvested for human consumption each year. Here we discuss the possibility that the largely prion disease resistant pig can be a clinically silent carrier of replicating prions.
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| 134. |
- Hammarström, Per, et al.
(författare)
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Protein compactness measured by fluorescence resonance energy transfer - Human carbonic anhydrase II Is considerably expanded by the interaction of GroEL
- 2001
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 276:24, s. 21765-21775
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Tidskriftsartikel (refereegranskat)abstract
- Nine single-cysteine mutants were labeled with 5-(2-iodoacetylaminoethylamino)naphthalene-1-sulfonic acid, an efficient acceptor of Trp fluorescence in fluorescence resonance energy transfer. The ratio between the fluorescence intensity of the 5-(2-acetylaminoethylamino)naphthalene-1-sulfonic acid (AEDANS) moiety excited at 295 nm (Trp absorption) and 350 nn (direct AEDANS absorption) was used to estimate the average distances between the seven Trp residues in human carbonic anhydrase II (HCA II) and the AEDANS label, Guanidine HCl denaturation of the HCA II variants was also performed to obtain a curve that reflected the compactness of the protein at various stages of the unfolding, which could serve as a scale of the expansion of the protein. This approach was developed in this study and was used to estimate the compactness of HCA II during heat denaturation and interaction with GroEL, It was shown that thermally induced unfolding of HCA II proceeded only to the molten globule state. Reaching this state was sufficient to allow HCA II to bind to GroEL, and the volume of the molten globule intermediate increased similar to2.2-fold compared with that of the native state. GroEL-bound HCA II expands to a volume three to four times that of the native state (to similar to 117,000 Angstrom (3)), which correlates well with a stretched and loosened-up HCA II molecule in an enlarged GroEL cavity, Recently, we found that HCA II binding causes such an inflation of the GroEL molecule, and this probably represents the mechanism by which GroEL actively stretches its protein substrates apart (Hammarstrom, P., Persson, M., Owenius, R., Lindgren, M., and Carlsson, U. (2000) J. Biol. Chem. 275, 22832-22838), thereby facilitating rearrangement of misfolded structure.
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| 135. |
- Hammarström, Per, 1972-, et al.
(författare)
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Protein denaturation and the denatured state
- 2005
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Ingår i: Encyclopedia of Life Sciences. - : Wiley-Blackwell.
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Bokkapitel (populärvet., debatt m.m.)abstract
- Protein denaturation experiments are routinely used to determine protein stability and to elucidate structural and dynamic effects of mutations, cofactors and ligands. Denatured states of proteins have gained wide interest in recent years owing to their fundamental importance in a wide variety of phenomena such as deciphering the protein folding problem and the molecular understanding of many diseases.
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| 136. |
- Hammarström, Per
(författare)
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Protein folding, misfolding and disease
- 2009
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Ingår i: FEBS Letters. - : John Wiley & Sons. - 0014-5793 .- 1873-3468. ; 583:16, s. 2579-2580
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Tidskriftsartikel (refereegranskat)
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| 137. |
- Hammarström, Per, 1972-, et al.
(författare)
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Protein substrate binding induces conformational changes in the chaperonin GroEL : A suggested mechanism for unfoldase activity
- 2000
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 275:30, s. 22832-22838
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Tidskriftsartikel (refereegranskat)abstract
- Chaperonins are molecules that assist proteins during folding and protect them from irreversible aggregation. We studied the chaperonin GroEL and its interaction with the enzyme human carbonic anhydrase II (HCA II), which induces unfolding of the enzyme. We focused on conformational changes that occur in GroEL during formation of the GroEL-HCA II complex. We measured the rate of GroEL cysteine reactivity toward iodo[2-(14)C]acetic acid and found that the cysteines become more accessible during binding of a cysteine free mutant of HCA II. Spin labeling of GroEL with N-(1-oxy1-2,2,5,5-tetramethyl-3-pyrrolidinyl)iodoacetamide revealed that this additional binding occurred because buried cysteine residues become accessible during HCA II binding. In addition, a GroEL variant labeled with 6-iodoacetamidofluorescein exhibited decreased fluorescence anisotropy upon HCA II binding, which resembles the effect of GroES/ATP binding. Furthermore, by producing cysteine-modified GroEL with the spin label N-(1-oxyl-2,2,5,5-tetramethyl-3-pyrrolidinyl)iodoacetamide and the fluorescent label 5-((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid, we detected increases in spin-label mobility and fluorescence intensity in GroEL upon HCA II binding. Together, these results show that conformational changes occur in the chaperonin as a consequence of protein substrate binding. Together with previous results on the unfoldase activity of GroEL, we suggest that the chaperonin opens up as the substrate protein binds. This opening mechanism may induce stretching of the protein, which would account for reported unfoldase activity of GroEL and might explain how GroEL can actively chaperone proteins larger than HCA II.
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| 138. |
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| 139. |
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| 140. |
- Hammarström, Per, et al.
(författare)
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Sequence-dependent denaturation energetics : A major determinant in amyloid disease diversity
- 2002
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 99:SUPPL. 4, s. 16427-16432
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Several misfolding diseases commence when a secreted folded protein encounters a partially denaturing microenvironment, enabling its self assembly into amyloid. Although amyloidosis is modulated by numerous environmental and genetic factors, single point mutations within the amyloidogenic protein can dramatically influence disease phenotype. Mutations that destabilize the native state predispose an individual to disease, however, thermodynamic stability alone does not reliably predict disease severity. Here we show that the rate of transthyretin (TTR) tetramer dissociation required for amyloid formation is strongly influenced by mutation (V30M, L55P, T119M, V122I), with rapid rates exacerbating and slow rates reducing amyloidogenicity. Although these rates are difficult to predict a priori, they notably influence disease penetrance and age of onset. L55P TTR exhibits severe pathology because the tetramer both dissociates quickly and is highly destabilized. Even though V30M and L55P TTR are similarly destabilized, the V30M disease phenotype is milder because V30M dissociates more slowly, even slower than wild type (WT). Although WT and V122I TTR have nearly equivalent tetramer stabilities, V122I cardiomyopathy, unlike WT cardiomyopathy, has nearly complete penetrance-presumably because of its 2-fold increase in dissociation rate. We show that the T119M homotetramer exhibits kinetic stabilization and therefore dissociates exceedingly slowly, likely explaining how it functions to protect V30M/T119M compound heterozygotes from disease. An understanding of how mutations influence both the kinetics and thermodynamics of misfolding allows us to rationalize the phenotypic diversity of amyloid diseases, especially when considered in concert with other genetic and environmental data.
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