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1.
A catalogue of Clostridium thermocellum endoglucanase, β-glucosidase and xylanase genes cloned in Escherichia coli 总被引:3,自引:0,他引:3
Geoffrey P. Hazlewood Marek P.M. Romaniec Keith Davidson Olivier Grépinet Pierre Béguin Jacqueline Millet Odette Raynaud Jean-Paul Aubert 《FEMS microbiology letters》1988,51(2-3):231-236
Abstract Two independent collections of clones containing Clostridium thermocellum genes involved in cellulose have been previously obtained at IAPGR, Cambridge, and at the Pasteur Institute, Paris. The two collections were compared for cross-hybridization, restriction maps and enzyme phenotypes. Truly distinct genes were one β-glucosidase gene, two xylanase genes, and fifteen endogluconase genes. Two of the cloned fragments contained extraneous DNA which was absent from their respective counterparts isolated in the other collection. The dicrepancies resulted from in vivo rearrangements which had occurred in either of the C. thermocellum NCIB 10682 stocks used to generate the two gene banks. 相似文献
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J P Mornon V Bissery C Gaboriaud A Thomas T Ojasoo J P Raynaud 《Journal of steroid biochemistry》1989,34(1-6):355-361
A new technique of protein sequence analysis, namely, Hydrophobic Cluster Analysis (HCA), has been used to align and compare the sequences of proteins belonging to the receptor superfamily (steroid, thyroid hormone and retinoic acid receptors) and serpin superfamily (corticosteroid binding globulin (CBG) and alpha 1-antitrypsin (alpha 1-AT]. By matching up clusters of hydrophobic amino-acids that oftenmost correspond to identifiable secondary structures (alpha-helices, beta-strands etc.), it has been possible to deduce the following information on the secondary structures of these proteins: CBG is structurally related to alpha 1-AT (HCA score greater than 80%), the structures of the hormone-binding domains of the steroid receptors that bind 3-keto-delta 4-steroids are closely interrelated (greater than 80%) but less closely related to that of the estrogen receptor (ER) (approximately 75%), vitamin D, retinoic acid and thyroid hormone receptors are structurally closely related (greater than or equal to 80%). Their secondary structures are, however, also related to that of the steroid receptors (approximately 70%), and a high degree of analogy exists between the structures of serpins and of the hormone-binding domains of members of the steroid superfamily (60-70%). HCA has clearly shown that a previous local sequence alignment of the estrogen receptor with other steroid receptors and cytochromes P450 has to be reconsidered. The published consensus steroid binding sequence previously identified in cytochromes is in fact 80 amino-acids upstream from its previously defined position. Other regions of contiguous sequence identity have also been identified which may be involved in the hydrophobic core of the protein or in steroid binding. Their positions have been indicated using the crystal structure of alpha 1-AT as a model. 相似文献
5.
Recognition specificity of the duplicated segments present in Clostridium thermocellum endoglucanase CelD and in the cellulosome-integrating protein CipA. 总被引:13,自引:9,他引:4
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S Salamitou O Raynaud M Lemaire M Coughlan P Bguin J P Aubert 《Journal of bacteriology》1994,176(10):2822-2827
The binding specificity of the duplicated segments borne by Clostridium thermocellum endoglucanase CelD and by the cellulosome-integrating protein CipA was investigated. The fusion protein CelC-DSCelD, in which the duplicated segment of CelD was fused to the COOH terminus of endoglucanase CelC, bound with an affinity of 4.7 x 10(7) M-1 to the fusion protein MalE-RDCipA, in which the seventh receptor domain of CipA was grafted onto the COOH terminus of the Escherichia coli maltose-binding protein MalE. The affinity of CelC-DSCelD for the homologous chimeric protein MalE-RDORF3p, carrying the receptor of the surface protein ORF3p, was 6.9 x 10(6) M-1. The fusion protein CelC-DSCipA, in which the duplicated segment of CipA was grafted onto the COOH terminus of CelC, did not bind detectably to MalE-RDCipA or MalE-RDORF3p. However, Western blotting (immunoblotting) experiments indicated that the duplicated segment of CipA was able to bind to a set of C. thermocellum proteins which are different from those recognized by the duplicated segment of CelD. These results argue against the hypothesis that ORF3p interacts with the duplicated segment of CipA. More probably, ORF3p binds to individual cellulases and hemicellulases harboring duplicated segments. 相似文献
6.
C. Wolfrom N. Raynaud J. Maigne S. Papathanassiou M. Conti N. Kadhom B. Hecquet F. Levi M. Gautier J. Deschatrette 《Cell biology and toxicology》1994,10(4):247-254
A human fibroblastic cell line transformed by the SV40-T antigen sequence and continuously cultured for 7 months displayed large periodic variations in cell proliferation. This contrasted with other characteristics of this cell line that remained constant: mosaic cell shape, absence of cell contact inhibition, and predominance of a hypodiploid population. Similar fluctuations in proliferative capacity were also found during the long-term growth of a transformed but nonimmortalized human fibroblastic line prior to senescence, and in the established hamster fibroblastic Nil cell line. This growth pattern suggests a recurrent stimulation of growth in these three transformed cell lines. The proliferation pattern from cultured transformed cells may thus be complex and requires further investigation. These variations presumably influence major cell functions. This observation has important implications for the analysis of data from such cell lines.Abbreviations I-SF
immortalized human skin fibroblasts
- T-SF
transformed human skin fibroblasts
- FBS
fetal bovine serum 相似文献
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8.
Litman GW; Rast JP; Shamblott MJ; Haire RN; Hulst M; Roess W; Litman RT; Hinds- Frey KR; Zilch A; Amemiya CT 《Molecular biology and evolution》1993,10(1):60-72
Immunoglobulins are encoded by a large multigene system that undergoes
somatic rearrangement and additional genetic change during the development
of immunoglobulin-producing cells. Inducible antibody and antibody-like
responses are found in all vertebrates. However, immunoglobulin possessing
disulfide-bonded heavy and light chains and domain-type organization has
been described only in representatives of the jawed vertebrates. High
degrees of nucleotide and predicted amino acid sequence identity are
evident when the segmental elements that constitute the immunoglobulin gene
loci in phylogenetically divergent vertebrates are compared. However, the
organization of gene loci and the manner in which the independent elements
recombine (and diversify) vary markedly among different taxa. One striking
pattern of gene organization is the "cluster type" that appears to be
restricted to the chondrichthyes (cartilaginous fishes) and limits
segmental rearrangement to closely linked elements. This type of gene
organization is associated with both heavy- and light-chain gene loci. In
some cases, the clusters are "joined" or "partially joined" in the germ
line, in effect predetermining or partially predetermining, respectively,
the encoded specificities (the assumption being that these are expressed)
of the individual loci. By relating the sequences of transcribed gene
products to their respective germ-line genes, it is evident that, in some
cases, joined-type genes are expressed. This raises a question about the
existence and/or nature of allelic exclusion in these species. The
extensive variation in gene organization found throughout the vertebrate
species may relate directly to the role of intersegmental
(V<==>D<==>J) distances in the commitment of the individual
antibody-producing cell to a particular genetic specificity. Thus, the
evolution of this locus, perhaps more so than that of others, may reflect
the interrelationships between genetic organization and function.
相似文献
9.
Subcloning of a DNA fragment encoding a single cohesin domain of the Clostridium thermocellum cellulosome-integrating protein CipA: purification, crystallization, and preliminary diffraction analysis of the encoded polypeptide.
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P. Bguin O. Raynaud M. K. Chaveroche A. Dridi P. M. Alzari 《Protein science : a publication of the Protein Society》1996,5(6):1192-1194
An Escherichia coli clone encoding a single cohesin domain of the cellulosome-integrating protein CipA from Clostridium thermocellum was constructed, and the corresponding polypeptide was purified, treated with papain, and crystallized from a PEG 8000 solution. Crystals exhibit orthorhombic symmetry, space group P2(1)2(1)2(1), with cell dimensions a = 37.7 A, b = 80.7 A, c = 93.3 A, and four or eight molecules in the unit cell. The crystals diffract X-rays to beyond 2 A resolution and are suitable for further crystallographic studies. 相似文献
10.
Catherine Iehl Sylvie Dlos Olivier Guirou Rothwell Tate Jean-Pierre Raynaud Pierre-Marie Martin 《The Journal of steroid biochemistry and molecular biology》1995,54(5-6)
The present study describes the independent expression of the type 1 and 2 isoforms of human 5α-reductase in the baculovirus-directed insect cell expression system and the selectivity of their inhibition. The catalytic properties and kinetic parameters of the recombinant isozymes were consistent with published data. The type 1 isoform displayed a neutral (range 6–8) pH optimum and the type 2 isoform an acidic (5–6) pH optimum. The type 2 isoform had higher affinity for testosterone than did the type 1 isoform (Km = 0.5 and 2.9 μM, respectively). Finasteride and turosteride were selective inhibitors of the type 2 isoform (Ki (type 2) = 7.3 and 21.7 nM compared to Ki (type 1) = 108 and 330 nM, respectively). 4-MA and the lipido-sterol extract of Serenoa repens (LSESr) markedly inhibited both isozymes (Ki (type 1) = 8.4 nM and 7.2 μg/ml, respectively; Ki (type 2) = 7.4 nM and 4.9 μg/ml, respectively). The three azasteroids were competitive inhibitors vs substrate, whereas LSESr displayed non-competitive inhibition of the type 1 isozyme and uncompetitive inhibition of the type 2 isozyme. These observations suggest that the lipid component of LSESr might be responsible for its inhibitory effect by modulating the membrane environment of 5α-reductase. Partially purified recombinant 5α-reductase type 1 activity was preserved by the presence of lipids indicating that lipids can exert either stimulatory or inhibitory effects on human 5α-reductase. 相似文献