Retraction Statement

[Bengil, EGT, Akbora, HD, Hadjioannou, L, Papageorgiou, M, Snape, R. A new species in town: New record of Hexanchus nakamurai Teng, 1962 from the Levantine Sea. J Appl Ichthyol. 2021; 37: 113- 119.  https://doi.org/10.1111/jai.14125 ] The above article from the Journal of Applied Ichthyology, published online on 1 November 2020 in Wiley Online Library ( https://onlinelibrary.wiley.com/doi/abs/10.1111/jai.14125 ), has been retracted by agreement between Elizabeth G. T. Bengil, Hasan D. Akbora, Louis Hadjioannou, Marios Papageorgiou and Robin Snape, the journal Editor-in-Chief, Christian Wolter, and John Wiley & Sons Ltd. The retraction has been agreed due to an unintentional but major scientific error invalidating the conclusions of the article.     

Retracted: Extracting the practices of paleogenomics: A study of ancient DNA labs and research in relation to Native Americans and Indigenous peoples

Retraction: Cortez, A. D., Lippert, D., Davis, J. L., Nicholas, G., Malhi, R. S., Weyrich, L. S., Claw, K. G., Bader, A. C., & Colwell, C. (2023). Extracting the practices of paleogenomics: A study of ancient DNA labs and research in relation to Native Americans and Indigenous peoples. American Journal of Biological Anthropology. https://doi.org/10.1002/ajpa.24714 . The above article, published online on 17 February 2023 in Wiley Online Library ( wileyonlinelibrary.com ), has been retracted by agreement between the authors, the journal Editor in Chief, Trudy Turner, and Wiley Periodicals LLC. The retraction has been agreed due to a former collaborator voiding permission for use of their early contribution to the team project.     

Book reviews

Book reviewed in this article:
B acterial C ell S tructure (Aspects of Microbiology 6) (1983). H.J. Rogers.
T he E lisa : E nzyme -L inked I mmunosorbent A ssay in V eterinary R esearch and D iagnosis (1982). Edited by R.C Wardley & J.R. Crowther.
G enetic R ecombination : U nderstanding the M echanisms (1982). H.L.K. Whitehouse.
M icrobial C ontrol of P lant P ests & D iseases (Aspects of Microbiology 7) (1983). J.W. Deacon.
M ethods in F ood and D airy M icrobiology (1982)     

BUCHBESPRECHUNGEN

S tephan , H.; B aron , G.; F rahm , H. D.: Comparative Brain Research in Mammals.
S uzuki , D. T.; G riffiths , A. J. F.; M iller , J. H.; L ewontin , R. C.: G enetik. Übersetzt von S. A chten und P. B öhm .
K ämpfe , L othar (ed.): Evolution und Stammesgeschichte der Organismen. Bearbeitet von 5 Fachwissenschaftlem. 3., neubearbeitete und erweiterte Auflage.     

Dynamic properties of biologically active synthetic heparin-like hexasaccharides

A complete study of the dynamics of two synthetic heparin-like hexasaccharides, D-GlcNHSO3-6-SO4-alpha-(1-->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHSO3-6-SO4-alpha-(1-->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHSO3-6-SO4-alpha-(1-->4)-L-IdoA-2-SO4-alpha-1-->iPr (1) and -->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHAc-6-SO4-alpha-(1-->4)-L-IdoA-alpha-(1-->4)-D-GlcNHSO3-alpha-(1-->4)-L-IdoA-2-SO4-alpha-1-->iPr (2), has been performed using 13C-nuclear magnetic resonance (NMR) relaxation parameters, T1, T2, and heteronuclear nuclear Overhauser effect (NOEs). Compound 1 is constituted from sequences corresponding to the major polysaccharide heparin region, while compound 2 contains a sequence never found in natural heparin. They differ from each other only in sulphation patterns, and are capable of stimulating fibroblast growth factors (FGFs)-1 induced mitogenesis. Both oligosaccharides exhibit a remarkable anisotropic overall motion in solution as revealed by their anisotropic ratios (tau /tau||), 4.0 and 3.0 respectively. This is a characteristic behaviour of natural glycosaminoglycans (GAG) which has also been observed for the antithrombin (AT) binding pentasaccharide D-GlcNHSO3-6-SO4-alpha-(1-->4)-D-GlcA-beta-(1-->4)-D-GlcNHSO3-(3,6-SO4)-alpha-(1-->4)-L-IdoA-2-SO4-alpha-(1-->4)-D-GlcNHSO3-6-SO4-alpha-1-->Me (3) (Hricovíni, M., Guerrini, M., Torri, G., Piani, S., and Ungarelli, F. (1995) Conformational analysis of heparin epoxide in aqueous solution. An NMR relaxation study. Carbohydr. Res., 277, 11-23). The motional properties observed for 1 and 2 provide additional support to the suitability of these compounds as heparin models in agreement with previous structural (de Paz, J.L., Angulo, J., Lassaletta, J.M., Nieto, P.M., Redondo-Horcajo, M., Lozano, R.M., Jiménez-Gallego, G., and Martín-Lomas, M. (2001) The activation of fibroblast growth factors by heparin: synthesis, structure and biological activity of heparin-like oligosaccharides. Chembiochem, 2, 673-685; Ojeda, R., Angulo, J., Nieto, P.M., and Martin-Lomas. M. (2002) The activation of fibroblast growth factors by heparin: synthesis and structural study of rationally modified heparin-like oligosaccharides. Can. J. Chem,. 80, 917-936; Lucas, R., Angulo, J., Nieto, P.M., and Martin-Lomas, M. (2003) Synthesis and structural studies of two new heparin-like hexasaccharides. Org. Biomol. Chem., 1, 2253-2266) and biological data (Angulo, J., Ojeda, R., de Paz, J.L., Lucas, R., Nieto, P.M., Lozano, R.M., Redondo-Horcajo, M., Giménez-Gallego, G., and Martín-Lomas, M. (2004) The activation of fibroblast growth factors (FGFs) by glycosaminoglycans: influence of the sulphation pattern on the biological activity of FGF-1. Chembiochem, 5, 55-61). Fast internal motions observed for the less sulphated compound 2, as compared with 1, may be related to their different behavior in stimulating FGF1-induced mitogenic activity.     

Retraction

Senapati, N., Griffiths, S., Hawkesford, M., Shewry, P. R., & Semenov, M. A. (2019). Large increase in yield is predicted by wheat ideotypes for Europe under future climate. Global Change Biology, https://doi.org/10.1111/gcb.14943 . [Epub ahead of print] The above article, first published online in Wiley Online Library (wileyonlinelibrary.com) on 4 December 2019, has been retracted by the journal Editor‐in‐Chief Steve Long, and John Wiley & Sons Ltd. Since publication of the above article, it was discovered that a substantial proportion of the results presented to the journal as original had in fact already been published by two of the authors in another journal. The editors apologize for any inconvenience the publication of this work may have caused to readers.     

I hear you Noggin

Noggin-mediated antagonism of BMP signaling is required for growth and patterning of the neural tube and somite McMahon, J.A. et al. Genes Dev. 12, 1438–1452Noggin, cartilage morphogenesis, and joint formation in the mammalian skeleton Brunet, L.J., McMahon, J.A., McMahon, A.P. and Harland, R.M. Science 280, 1455–1457Endogenous and ectopic expression of noggin suggests a conserved mechanism for regulation of BMP function during limb and somite patterning Capdevila, J. and Johnson, R.L. Dev. Biol. 197, 205–217     

Books

Books reviewed in this article: Adar , M. (ed.). 1993. Bird Sounds (in Hebrew) Baumel , J.J., King , AS., Breazile , J.E., Evans , H.E. & Van den Berge Bergman , H.-H. 1993. Der Buchfink. Born , E.G. & Flores , D. 1993. The Mississippi Kite. Bhushan , B., Fry , G., Hibi , A., Mundkur , T., Prawiradilaga , D.M., Sonobe , K. & Usui , S. 1993. Clement , P., Harris , A. & Davis , J. 1993. Finches & Sparrows. An identification guide. Crawley , M.J. 1993. GLIM for Ecologists. Methods in ecology series. Dowsett , R.J. & Forbes -Watson , A. 1993. Checklist of Birds of the Afrotropical and Malagasy Regions. Dowsett , R.J. & Dowsett -Lemaire , F. 1993. A Contribution to the Distribution and Taxonomy of Afrotropical and Malagasy Birds. Dvorak , M., Ranner . A. & Berg . H.-M. 1993. Atlas der Brutvögel Österreichs Glutz von Blotzheim , U.N. & Bauer , K.M. 1991. Handbuch der Vogel Mitteleuropas. Band 12/I and II: Passeriformes (3. Teil). Sylviidae. Harrison , C. & Greensmth , A. 1993. Birds of the World. Eyewitness Handbooks Hume , R. & Pearson , B. Seabirds. Martin , B. P. & Proud , A. 1993. Wildfowl of the British Isles and North-west Europe. Maclean , G.L. (ed.). 1993. Robert's Birds of Southern Africa. Mc Ferran , J.B. & Mc Nulty , M.S. (eds). Mc Gregor , P.K. (ed.). Mc Nicholl , K.M. & Cranmer -Byng , J.L. (eds). 1994. Ornithology in Ontario. Muñiz , A.M. & Rosello , E. (eds). 1993. Archaeornithology: Birds and the archaeological record. Archaeofauna (Revista de la Asociacion Española de Arqueozoología): 2. Norman , D. 1994. The Fieldfare. Ogilvie , M. & Pearson , B. 1994. Wildfowl Osing , H. 1993. Der Flußregenpfeifer (Charadrius dubius). Redig , P.T., Cooper , J.E., Remple , J.D. & Hunter Ryabitsev , V.K. 1993. Territorial Relationships and Bird Community Dynamics in the Subarctic (In Russian, English contents.) Schepers , F.J. & Marteijn , C.L. (eds). 1993. Coastal Waterbirds in Gabon. Smley , C.G. & Monroe , B.L., Jr . 1993. A Supplement to Distribution and Taxonomy of Birds of the World. Monroe , B.L., Jr . & Sibley , C.G. 1993. A World Checklist of Buds. Whylde , A. 1993. Threatened Mammals, Birds, Amphibians and Fish in Ireland. Irish Red Data Book 2: Vertebrates. Alderton , D. 1993. The Handbook of Cage and Aviary Birds. Boutin , J. 1993. Les Oiseaux de Camargue. Bransbury , J. 1992. Where to Find Birds in Australia. Camphuysen , C.J., Ensor , K., Furness , R.W., Garthe , S., Hüppop , O., Leaper , G., Offringer , H. & Tasker , M.L. 1993. Seabirds Feeding on Discards in Winter in the North Sea: Final report to the European Commission. Castroviejo , J. 1993. Mappa del Parque nacional de Doñana. Davis , S.M. & Ogden . J.C. (eds). 1994. Everglades: The ecosystem and its restoration. Department of the Environment . 1994. Biodiversity: The UK action plan. Epple , W. 1993. Eulen: Die geheimnisvollen Vagel der Nacht. Ken-nenlernen, erleben, schützen. Fernández -Cordeiro , A. & Dominguez , J. (eds). 1991. Actas do Pri-meiro Congreso Galego de Ornitoloxía. Cursos e Congressos da Universidade de Santiago de Compostela no. Finlayson , C.M., Chuikov , Y.S., Prentice , R.C. & Fischer , W. (eds). 1993. Biogeography of the Lower Volga. Russia: An overview. Fisher , C. & Jones , P. (eds). 1993. Papers from the History of Ornithology Conference Gales , R. 1993. Co-operative Mechanisms for the Conservation of Albatross. Garcia , E. & Paterson , A. 1994. Where to Watch Buds in Southern Spain, Andalucía. Extremadura and Gibraltar. Grishchenko , V.N. & Skil's‘kii , I.V. (eds). 1994. Materials of the 1st Conference of Young Ornithologists Ukraine, March 46.1994, Lutsk (in Russian). Library of journal “Berkut” 1. Holden , P. & Langman , M. 1994. Migrants and Migration. Kaufman , J. & Meng , H. 1992. Falcons Return. Keller , C.E. & Keller , T.C. 1993. Birds of Indianapolis: A guide to the region. Mc Eneaney , T. 1993. The Birder's Guide to Montana. Merritt , J.F. & Hannakan , C.J. (eds). 1992. Guide to Biological Field Stations: Directory of members Meschini , E. & Frugis , S. (eds). 1993. Atlante degli uccelli nidificanti in Italia. Supplemento alle Ricerche di Biologia deb Selvaggina. Nethercoat , I. & Langman , M. 1994. Bird Identification and Field Craft. Hamlyn Young Ornithologists' Guides Oman Bird Records Commitee . 1994. Oman Bird List. The official list of the birds of the Sultanate of Oman. Renno , K.O. (compiler). 1993. Eesti Linnutatlas: Eesti haudelindude levikuatlas. Sen -Hsiong Wu & Hsiou Yin Yang . 1991. A guide to the birds of Taiwan (in Chinese). Simpson , K. & Day , N. 1994. Field Guide to the Birds of Australia. The most complete one-volume book of identification. Thalmann , G. (ed.). 1994. Thorburn's Atlas of European Birds. Tomer , J.S. & Brodhead , M.J. (eds). 1992. A Naturalist in Indian Territory. The journals of S.W. Woodhouse, 1849–50. Watkins , D. 1993. A National Plan for Shorebird Conservation in Australia. Western Hemisphere Shorebird Reserve Network . 1993. Western Hemisphere Shorebird Reserve Network site profiles. World Conservation Monitoring Centre Cambridge Wynne , G. 1994. Biodiversity Challenge: An agenda for conservation action in the UK.     

Book Review

B iotechnology: A T extbook OF I ndustrial M icrobiology (1984). W. Crueger & A. Crueger.
I ntroduction TO M odern M ycology 2nd edition B asic M icrobiology Volume 7 (1984). J. W. Deacon.
L aboratory A nimal M edicine (1984). Edited by J. G. Fox, B. J. Cohen & F. M. Loew.
B acterial V accines (1984). Edited by R. Germanier.
M onoclonal A ntibodies: P rinciples AND P ractice P roduction AND A pplication IN C ell B iology , B iochemistry AND I mmunology (1983) J. W. Goding.
A dvances IN B iotechnological P rocesses Volume 3 (1984). Edited by A. Mizrahi & A. L. van Wezel.
C urrent D evelopment IN B iological N itrogen F ixation (1984). Edited by N. S. Subba Roa.     

Calmodulin differentially modulates Smad1 and Smad2 signaling

The members of the Smad protein family are intracellular mediators of transforming growth factor beta (TGF-beta) signaling. Smad1 transduces bone morphogenetic protein signals, inducing formation of ventral mesoderm in Xenopus embryos, whereas Smad2 transduces activin/TGF-beta signals, generating dorsal mesoderm. Calmodulin directly binds to many Smads and was shown to down-regulate Smad2 activity in a cell culture system (Zimmerman, C. M., Kariapper, M. S. T., and Mathews, L. S. (1997) J. Biol. Chem. 273, 677-680). Here, we extend those data and demonstrate that calmodulin alters Smad signaling in living embryos, increasing Smad1 activity while inhibiting Smad2 function. To characterize this regulation, we undertook a structure-function analysis and found that calmodulin binds to two distinct and conserved regions in both Smad1 and Smad2. Receptor tyrosine kinase signaling also modifies Smad activity (Kretzschmar, M., Doody, J., and Massagué, J. (1997) Nature 389, 618-622; Kretzschmar, M., Doody, J., Timokhina, I., and Massagué, J. (1999) Genes Dev. 13, 804-816; de Caestecker, M. P., Parks, W. T., Frank, C. J., Castagnino, P., Bottaro, D. P., Roberts, A. B., and Lechleider, R. J. (1998) Genes Dev. 12, 1587-1592). We show that calmodulin binding to Smads inhibits subsequent Erk2-dependent phosphorylation of Smads and vice versa. These observations suggest the presence of a cross-talk between three major signaling cascades as follows: Ca(2+)/calmodulin, receptor tyrosine kinase, and TGF-beta pathways.     

Solution structure of microcin J25, the single macrocyclic antimicrobial peptide from Escherichia coli.

The three-dimensional solution structure of microcin J25, the single cyclic representative of the microcin antimicrobial peptide class produced by enteric bacteria, was determined using two-dimensional 1H NMR spectroscopy and molecular modeling. This hydrophobic 21-residue peptide exhibits potent activity directed to Gram-negative bacteria. Its primary structure, cyclo(-V1GIGTPISFY10GGGAGHVPEY20F-), has been determined previously [Blond, A., Péduzzi, J., Goulard, C., Chiuchiolo, M. J., Barthélémy, M., Prigent, Y., Salomón, R.A., Farías, R.N., Moreno, F. & Rebuffat, S. (1999) Eur. J. Biochem., 259, 747-755]. Conformational parameters (3JNHCalphaH coupling constants, quantitative nuclear Overhauser enhancement data, chemical shift deviations, temperature coefficients of amide protons, NH-ND exchange rates) were obtained in methanol solution. Structural restraints consisting of 190 interproton distances inferred from NOE data, 11 phi backbone dihedral angle and 9 chi1 angle restraints derived from the coupling constants and three hydrogen bonds in agreement with the amide exchange rates were used as input for simulated annealing calculations and energy minimization in the program XPLOR. Microcin J25 adopts a well-defined compact structure consisting of a distorted antiparallel beta sheet, which is twisted and folded back on itself, thus resulting in three loops. Residues 7-10 and 17-20 form the more regular part of the beta sheet. The region encompassing residues Gly11-His16 consists of a distorted beta hairpin, which divides into two small loops and is stabilized by an inverse gamma turn and a type I' beta turn. The reversal of the chain leading to the Phe21-Pro6 loop results from a mixed beta/gamma turn. A cavity, in which the hydrophilic Ser8 side-chain is confined, is delimited by two crab pincer-like regions that comprise residues 6-8 and 18-1.     

Book Reviews

Book reviewed in this article:
Zwilling, B. S. & Einstein, T. K. 1994. Macrophage-Pathogen Interactions
Maizels, R. M., Blaxter, M. L., Robertson, B. D. & Selkirk, M. E. 1992. Parasite Antigens, Parasite Genes: A Laboratory Manual for Molecular Parasitology     

Inhibition of Transmitter Release and Attenuation of Anti-retroviral-associated and Tibial Nerve Injury-related Painful Peripheral Neuropathy by Novel Synthetic Ca2+ Channel Peptides

N-type Ca²⁺ channels (CaV2.2) are a nidus for neurotransmitter release and nociceptive transmission. However, the use of CaV2.2 blockers in pain therapeutics is limited by side effects resulting from inhibition of the physiological functions of CaV2.2 within the CNS. We identified an anti-nociceptive peptide (Brittain, J. M., Duarte, D. B., Wilson, S. M., Zhu, W., Ballard, C., Johnson, P. L., Liu, N., Xiong, W., Ripsch, M. S., Wang, Y., Fehrenbacher, J. C., Fitz, S. D., Khanna, M., Park, C. K., Schmutzler, B. S., Cheon, B. M., Due, M. R., Brustovetsky, T., Ashpole, N. M., Hudmon, A., Meroueh, S. O., Hingtgen, C. M., Brustovetsky, N., Ji, R. R., Hurley, J. H., Jin, X., Shekhar, A., Xu, X. M., Oxford, G. S., Vasko, M. R., White, F. A., and Khanna, R. (2011) Suppression of inflammatory and neuropathic pain by uncoupling CRMP2 from the presynaptic Ca²⁺ channel complex. Nat. Med. 17, 822–829) derived from the axonal collapsin response mediator protein 2 (CRMP2), a protein known to bind and enhance CaV2.2 activity. Using a peptide tiling array, we identified novel peptides within the first intracellular loop (CaV2.2(388–402), “L1”) and the distal C terminus (CaV1.2(2014–2028) “Ct-dis”) that bound CRMP2. Microscale thermophoresis demonstrated micromolar and nanomolar binding affinities between recombinant CRMP2 and synthetic L1 and Ct-dis peptides, respectively. Co-immunoprecipitation experiments showed that CRMP2 association with CaV2.2 was inhibited by L1 and Ct-dis peptides. L1 and Ct-dis, rendered cell-penetrant by fusion with the protein transduction domain of the human immunodeficiency virus TAT protein, were tested in in vitro and in vivo experiments. Depolarization-induced calcium influx in dorsal root ganglion (DRG) neurons was inhibited by both peptides. Ct-dis, but not L1, peptide inhibited depolarization-stimulated release of the neuropeptide transmitter calcitonin gene-related peptide in mouse DRG neurons. Similar results were obtained in DRGs from mice with a heterozygous mutation of Nf1 linked to neurofibromatosis type 1. Ct-dis peptide, administered intraperitoneally, exhibited antinociception in a zalcitabine (2′-3′-dideoxycytidine) model of AIDS therapy-induced and tibial nerve injury-related peripheral neuropathy. This study suggests that CaV peptides, by perturbing interactions with the neuromodulator CRMP2, contribute to suppression of neuronal hypersensitivity and nociception.     

Degradation of transcription factor Nrf2 via the ubiquitin-proteasome pathway and stabilization by cadmium

Nrf2 mediates inducer-dependent activation of the heme oxygenase-1 (HO-1) gene (Alam, J., Stewart, D., Touchard, C., Boinapally, S., Choi, A. M., and Cook, J. L. (1999) J. Biol. Chem. 274, 26071-26078), but the mechanism by which HO-1 inducers regulate Nrf2 function is not known. Treatment of mouse hepatoma (Hepa) cells with 50 microm CdCl(2) increased the amount of Nrf2 protein in a time-dependent manner; induction was observed within 30 min, prior to the accumulation of HO-1 mRNA. Cadmium did not significantly affect the steady-state level of Nrf2 mRNA or the initial rate of Nrf2 protein synthesis but increased the half-life of Nrf2 from approximately 13 to 100 min. Proteasome inhibitors, but not other protease inhibitors, enhanced the expression of Nrf2, and ubiquitinylated Nrf2 was detected after proteasome inhibition. Cycloheximide inhibited cadmium-stimulated Nrf2 expression and DNA binding activity and attenuated HO-1 mRNA accumulation. Conversely, proteasome inhibitors enhanced HO-1 mRNA and protein accumulation by a Nrf2-dependent mechanism. Together, these results indicate that Nrf2 is targeted for rapid degradation by the ubiquitin-proteasome pathway and that cadmium delays the rate of Nrf2 degradation leading to ho-1 gene activation.     

Review

Book reviewed in this article:
Oyen, L. P. A. & Lemmens, R. H. M. J. (eds). 2002. Plant resources of tropical Africa—Precursor.
Oyen, L. P. A. & Lemmens, R. H. M J. (eds). 2002. Ressources végétales de rAfrique tropicale—Précurseur.
Bosch, C. H., Siemonsma, J. S., Lemmens, R. H. M. J. & Oyen L. P. A. (eds). 2002. Plant resources of tropical Africa/Ressources végétales de l'Afrique tropicale.     

Retraction Statement: Comparison of nitrogen inputs and accumulation in 210Pb‐dated peat cores: Evidence for biological N2‐fixation in Central European peatlands despite decades of atmospheric N pollution

“Comparison of nitrogen inputs and accumulation in ²¹⁰Pb‐dated peat cores: Evidence for biological N₂‐fixation in Central European peatlands despite decades of atmospheric N pollution” https://doi.org/10.1111/gcb.14505 , by Martin Novak, Melanie A. Vile, Jan Curik, Bohuslava Cejkova, Jiri Barta, Marketa Stepanova, Ivana Jackova, Frantisek Buzek, Leona Bohdalkova, Eva Prechova, Frantisek Veselovsky, Marie Adamova, Ivana Valkova and Arnost Komarek. The above article, first published online in Wiley Online Library (wileyonlinelibrary.com) in Global Change Biology, has been retracted by agreement between the authors, the journal Editor‐in‐Chief, Stephen P. Long, and John Wiley & Sons Ltd. Since publication of the above article, it was brought to the attention of the authors that the peat accretion rates violate reasonable ranges of peatland C/N/P stoichiometry, placing the quantitative conclusions of the article in serious error. The authors apologize for any inconvenience the publication of this work may have caused our readers. REFERENCE Novak, M., Vile, M. A., Cejkova, B., Barta, J., Stepanova, M., Jackova, I., Buzek, F., Bohdalkova, L., Prechova, E., Veselovsky, F., Adamova, M., Valkova, I., & Komarek, A. (2018). Comparison of nitrogen inputs and accumulation in ²¹⁰Pb‐dated peat cores: Evidence for biological N₂‐fixation in Central European peatlands despite decades of atmospheric N pollution. Global Change Biology.. https://doi.org/10.1111/gcb.14505     

DSC studies of a family of natively disordered fragments from Escherichia coli thioredoxin: surface burial in intrinsic coils

The accumulating data from proteome analysis indicates that numerous proteins have segments and/or domains, involved in regulatory functions of the eukaryotic cell, which are entirely unstructured under physiological conditions, challenging the structure-function paradigm. Although many such natively unfolded proteins have been structurally analyzed by NMR spectroscopy, little is known about solvent inaccessible surfaces in premolten globules and intrinsic coils. Recent DSC studies of two protein fragments have shown a promising way to estimate the predominantly hydrophobic buried surfaces [Georgescu, R. E., García-Mira, M. M., Tasayco, M. L., and Sánchez-Ruiz, J. M. (2001) Eur. J. Biochem. 268, 1-10]. Here we report a systematic heat capacity analysis of a family of natively disordered complementary fragments of oxidized Escherichia coli thioredoxin (1-31/32-108, 1-37/38-108, 1-50/51-108, and 38-73) which provides insights into the local and nonlocal interactions contributing to the burial of predominantly hydrophobic surface in intrinsic coils.     

Immunogobulin-lipid interaction: A model membrane study

We recently presented evidence (Vandenbranden, M., De Coen, J.L., Jeener, R., Kanarek, L. and Ruysschaert, J.M. (1981) Mol. Immunol. 8, 621–631) for the existence of two conformational rabbit serum IgG immunoglobulin isomers. In the present report, their capacity to interact with lipid is investigated in model membranes. (1) One isomer, IgG(H), behaves like several intrinsic membrane proteins: it induces a large surface pressure increase when injected under a lipid monolayer in the close packed state and increases by 20-fold the conductance of a planar bilayer. The other isomer, IgG(S) doesn't interact significantly with the lipids. (2) IgG(H) marked a preference for monolayers made of lipids with a negatively charged polar headgroup and bearing unsaturations in their acyl chains. Penetration is stronger with lipid monolayer in the fluid state than in the rigid state. (3) As previously shown (Vandenbranden, M., De Coen, J.L., Jeener, R., Kanarek, L. and Ruysschaert, J.M. (1981) Mol. Immunol. 18, 621–631), circular dichroïsm spectra and antigen precipitation tests don't allow to detect any difference in the overall secondary conformation and antigen recognition properties of the two isomers. (4) Papaïn cleavage of the hinge region suppresses the hydrophobic properties of IgG towards lipid monolayers. (5) The hypothesis of a binding of the hinge region with the lipid bilayer is discussed.