Search results for "RICH"
showing 10 items of 3360 documents
Microbiological control of soil-borne phytopathogenic fungi with special emphasis on wilt-inducing Fusarium oxysporum
2009
Contents Summary 529 I. Biological control of plant diseases: state of the art 530 II. Main modes of action of biological control agents 530 III. The protective strains of F. oxysporum: an unexplored model 532 IV. Future directions for the study of the protective capacity of strains of F. oxysporum 539 V. How to make biological control successful in the field? 540 References 541 Summary Plant diseases induced by soil-borne plant pathogens are among the most difficult to control. In the absence of effective chemical control methods, there is renewed interest in biological control based on application of populations of antagonistic micro-organisms. In addition to Pseudomonas spp. a…
The Closed/Open Model for Lipase Activation. Addressing Intermediate Active Forms of Fungal Enzymes by Trapping of Conformers in Water-Restricted Env…
2001
The behavior of prototypic fungal lipases in a water-restricted environment has been investigated by exploiting the reported experimental strategy that allows the trapping (freeze-drying) of the enzyme in the conformation present in aqueous solution and to subsequently assay it in nonaqueous media [Mingarro, I., Abad, C., and Braco, L. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 3308-3312]. We now report, using simple esterification as well as acidolysis (triglycerides as substrates) as nonaqueous model reactions, that the presence of a detergent (n-octyl-beta-glucopyranoside) in the freeze-drying buffer, at concentrations below the critical micellar concentration, generates different catalyti…
Crystal structure of bacteriophage fr capsids at 3.5 A resolution.
1994
The structure of recombinant capsids of the bacterial virus fr has been determined by X-ray crystallography at 3.5 A resolution. The capsids were produced by expressing the fr coat protein in Escherichia coli, the natural host of the virus, and are probably essentially identical to the protein shell of the native virus. The structure was determined using molecular replacement with the protein shell of the related MS2 virus, and refined to a crystallographic R-factor of 0.228. A comparison of the protein shells of the viruses shows that they are very similar, and indicates that they may have a similar regulation of the assembly of the quasi-symmetrical protein shell.
Expression and renaturation of the N-terminal extracellular domain of torpedo nicotinic acetylcholine receptor alpha-subunit.
1998
The N-terminal extracellular region (amino acids 1-209) of the alpha-subunit of the nicotinic acetylcholine receptor (nAChR) from Torpedo marmorata electric tissue was expressed as inclusion bodies in Escherichia coli using the pET 3a vector. Employing a novel protocol of unfolding and refolding, in the absence of detergent, a water-soluble globular protein of 25 kDa was obtained displaying approximately 15% alpha-helical and 45% beta-structure. The fragment bound alpha-[3H]bungarotoxin in 1:1 stoichiometry with a KD value of 0.5 nM as determined from kinetic measurements (4 nM from equilibrium binding). The kinetics of association of toxin and fragment were of second order, with a similar …
The protease domain of procollagen C-proteinase (BMP1) lacks substrate selectivity, which is conferred by non-proteolytic domains.
2007
Abstract Procollagen C-proteinase (PCP) removes the C-terminal pro-peptides of procollagens and also processes other matrix proteins. The major splice form of the PCP is termed BMP1 (bone morphogenetic protein 1). Active BMP1 is composed of an astacin-like protease domain, three CUB (complement, sea urchin Uegf, BMP1) domains and one EGF-like domain. Here we compare the recombinant human full-length BMP1 with its isolated proteolytic domain to further unravel the functional influence of the CUB and EGF domains. We show that the protease domain alone cleaves truncated procollagen VII within the short telopeptide region into fragments of similar size as the full-length enzyme does. However, u…
Expression and glycosylation studies of human FGF receptor 4
2001
Fibroblast growth factor receptor subtype 4 (FGFR4) has been shown to have special activation properties and just one splicing form, unlike the other FGFRs. FGFR4 overexpression is correlated with breast cancer and therefore FGFR4 is a target for drug design. Our aim is to overexpress high amounts of homogeneous FGFR4 extracellular domain (FGFR4ed) for structural studies. We show that baculovirus-insect cell-expressed FGFR4ed is glycosylated on three (N88, N234, and N266) of the six possible N-glycosylation sites but is not O-glycosylated. The deglycosylated triple mutant was expressed and had binding properties similar to those of glycosylated FGFR4ed, but was still heterogeneous. Large am…
Biotechnical applications of small heat shock proteins from bacteria.
2012
The stress responses of most bacteria are thought to involve the upregulation of small heat shock proteins. We describe here some of the most pertinent aspects of small heat shock proteins, to highlight their potential for use in various applications. Bacterial species have between one and 13 genes encoding small heat shock proteins, the precise number depending on the species considered. Major efforts have recently been made to characterize the protein protection and membrane stabilization mechanisms involving small heat shock proteins in bacteria. These proteins seem to be involved in the acquisition of cellular heat tolerance. They could therefore potentially be used to maintain cell via…
Polar/Ionizable Residues in Transmembrane Segments: Effects on Helix-Helix Packing
2012
The vast majority of membrane proteins are anchored to biological membranes through hydrophobic alpha-helices. Sequence analysis of high-resolution membrane protein structures show that ionizable amino acid residues are present in transmembrane (TM) helices, often with a functional and/or structural role. Here, using as scaffold the hydrophobic TM domain of the model membrane protein glycophorin A (GpA), we address the consequences of replacing specific residues by ionizable amino acids on TM helix insertion and packing, both in detergent micelles and in biological membranes. Our findings demonstrate that ionizable residues are stably inserted in hydrophobic environments, and tolerated in t…
Mutational analyses of YqjA, a Tvp38/DedA protein of E. coli
2015
AbstractMembrane proteins of the DedA/Tvp38 protein family are involved in membrane integrity and virulence of pathogenic organisms. However, the structure and exact function of any member of this large protein family are still unclear. In the present study we analyzed the functional and structural properties of a DedA homolog. Purified YqjA variants from Escherichia coli are detectable in different oligomeric states and specific homo-interaction of YqjA monomers in the membrane were confirmed by formation of a disulfide bond in the C-terminal transmembrane helix. Moreover, alanine scanning mutagenesis exhibited different interaction sites crucial for YqjA activity vs. dimer formation.
Novel avidin-like protein from a root nodule symbiotic bacterium, Bradyrhizobium japonicum.
2005
Bradyrhizobium japonicum is an important nitrogenfixing symbiotic bacterium, which can form root nodules on soybeans. These bacteria have a gene encoding a putative avidin- and streptavidin-like protein, which bears an amino acid sequence identity of only about 30% over the core regions with both of them. We produced this protein in Escherichia coli both as the full-length wild type and as a C-terminally truncated core form and showed that it is indeed a high affinity biotin-binding protein that resembles (strept)avidin structurally and functionally. Because of the considerable dissimilarity in the amino acid sequence, however, it is immunologically very different, and polyclonal rabbit and…