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Motif Similar (motif + similar)

Distribution by Scientific Domains

Chemistry	60%
Life Sciences	40%

Selected Abstracts

Structural model for an AxxxG-mediated dimer of surfactant-associated protein C

FEBS JOURNAL, Issue 11 2004
Visvaldas Kairys
The pulmonary surfactant prevents alveolar collapse and is required for normal pulmonary function. One of the important components of the surfactant besides phospholipids is surfactant-associated protein C (SP-C). SP-C shows complex oligomerization behavior and a transition to ,-amyloid-like fibril structures, which are not yet fully understood. Besides this nonspecific oligomerization, MS and chemical cross-linking data combined with CD spectra provide evidence of a specific, mainly ,-helical, dimer at low to neutral pH. Furthermore, resistance to CNBr cleavage and dual NMR resonances of porcine and human recombinant SP-C with Met32 replaced by isoleucine point to a dimerization site located at the C-terminus of the hydrophobic ,-helix of SP-C, where a strictly conserved heptapeptide sequence is found. Computational docking of two SP-C helices, described here, reveals a dimer with a helix,helix interface that strikingly resembles that of glycophorin A and is mediated by an AxxxG motif similar to the experimentally determined GxxxG pattern of glycophorin A. It is highly likely that mature SP-C adopts such a dimeric structure in the lamellar bilayer systems found in the surfactant. Dimerization has been shown in previous studies to have a role in sorting and trafficking of SP-C and may also be important to the surfactant function of this protein. [source]

A teratocyte gene from a parasitic wasp that is associated with inhibition of insect growth and development inhibits host protein synthesis

INSECT MOLECULAR BIOLOGY, Issue 5 2003
D. L. Dahlman
Abstract After parasitization, some wasps induce hosts prematurely to initiate metamorphic development that is then suspended in a postwandering, prepupal state. Following egression of the parasite larva, the host remains in this developmentally arrested state until death. Teratocytes, cells released at egg hatch from extra-embryonic serosal membranes of some wasp parasites, inhibit growth and development when injected into host larvae independent of other parasite factors (e.g. venom, polydnavirus). Synthesis of some developmentally regulated, abundantly expressed Heliothis virescens host proteins is inhibited in hosts parasitized by Microplitis croceipes and by teratocyte injection. A cDNA encoding a 13.9 kDa protein (TSP14) that inhibited protein synthesis, growth and development was isolated from a protein fraction secreted by teratocytes. TSP14 appears to be responsible, in part, for the teratocyte-mediated inhibition of host growth and development. Interestingly, this cDNA encoded a cysteine-rich amino acid motif similar to that described from Campoletis sonorensis polydnavirus, a mutualistic virus that enables wasp parasitization of lepidopteran larvae. Moreover, TSP14 inhibited protein synthesis in a dose-dependent manner in rabbit reticulocyte lysate and wheat germ extract translation systems. We hypothesize that some wasp parasites inhibit translation as a general means to regulate and redirect lepidopteran host physiology to support endoparasite development. [source]

The X-ray crystal structure of PA1607 from Pseudomonas aureginosa at 1.9 Å resolution,a putative transcription factor

PROTEIN SCIENCE, Issue 3 2007
Edyta A.L. Sieminska
Abstract The structure of the PA1607 protein from Pseudomonas aureginosa was determined at 1.85 Å resolution using the Se-Met multiwavelength anomalous diffraction (MAD) technique. PA1607 forms a dimer and adopts a winged-helix motif similar to the MarR family of transcription regulators, though it has an unusual dimerization profile. The DNA-binding regions and a putative metal-binding site are not conserved in PA1607. [source]

Guanidinium Alkynesulfonates with Single-Layer Stacking Motif: Interlayer Hydrogen Bonding Between Sulfonate Anions Changes the Orientation of the Organosulfonate R Group from "Alternate Side" to "Same Side"

CHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2010
Karim Bouchmella
Abstract Hydrolyses of HCCSO3SiMe3 (1) and CH3CCSO3SiMe3 (2) lead to the formation of acetylenic sulfonic acids HCCSO3H,2.33,H2O (3) and CH3CCSO3H,1.88,H2O (4). These acids were reacted with guanidinium carbonate to yield [+C(NH2)3][HCCSO3,] (5) and [+C(NH2)3][CH3CCSO3,] (6). Compounds 1,6 were characterized by spectroscopic methods, and the X-ray crystal structures of the guanidinium salts were determined. The X-ray results of 5 show that the guanidinium cations and organosulfonate anions associate into 1D ribbons through (8) dimer interactions, whereas association of these ions in 6 is achieved through (8) and (6) interactions. The ribbons in 5 associate into 2D sheets through (8) dimer interactions and (12) rings, whereas those in 6 are connected through (6) and (8) dimer interactions and (14) rings. Compound 6 exhibits a single-layer stacking motif similar to that found in guanidinium alkane- and arenesulfonates, that is, the alkynyl groups alternate orientation from one ribbon to the next. The stacking motif in 5 is also single-layer, but due to interlayer hydrogen bonding between sulfonate anions, the alkynyl groups of each sheet all point to the same side of the sheet. [source]

Calcium/calmodulin-dependent protein kinase type IV is a target gene of the Wnt/,-catenin signaling pathway,

JOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2009
Macarena S. Arrázola
Calcium/calmodulin-dependent protein kinase IV (CaMKIV) plays a key role in the regulation of calcium-dependent gene expression. The expression of CaMKIV and the activation of CREB regulated genes are involved in memory and neuronal survival. We report here that: (a) a bioinformatic analysis of 15,476 promoters of the human genome predicted several Wnt target genes, being CaMKIV a very interesting candidate; (b) CaMKIV promoter contains TCF/LEF transcription motifs similar to those present in Wnt target genes; (c) biochemical studies indicate that lithium and the canonical ligand Wnt-3a induce CaMKIV mRNA and protein expression levels in rat hippocampal neurons as well as CaMKIV promoter activity; (d) treatment of hippocampal neurons with Wnt-3a increases the binding of ,-catenin to the CaMKIV promoter: (e) In vivo activation of the Wnt signaling improve spatial memory impairment and restores the expression of CaMKIV in a mice double transgenic model for Alzheimer's disease which shows decreased levels of the kinase. We conclude that CaMKIV is regulated by the Wnt signaling pathway and that its expression could play a role in the neuroprotective function of the Wnt signaling against the Alzheimer's amyloid peptide. J. Cell. Physiol. 221: 658,667, 2009. © 2009 Wiley-Liss, Inc. [source]