scholarly journals The two major membrane skeletal proteins (articulins) of Euglena gracilis define a novel class of cytoskeletal proteins.

1992 ◽  
Vol 118 (6) ◽  
pp. 1465-1475 ◽  
Author(s):  
J A Marrs ◽  
G B Bouck
Keyword(s):  
Amino Acid ◽  
Fusion Protein ◽  
Euglena Gracilis ◽  
Cytoskeletal Proteins ◽  
Cdna Clones ◽  
Thin Sections ◽  
Core Domain ◽  
The Core ◽  
Amino Acid Repeats ◽  
Peptide Maps

60% of the peripheral membrane skeleton of Euglena gracilis consists of equimolar amounts of two proteins (articulins) with M(r)s in SDS gels of 80 and 86 kD. To understand eventually how these proteins assemble and function in maintaining cell form and membrane integrity we have undertaken a molecular characterization of articulins. A lambda gt11 expression library constructed from Euglena gracilis mRNAs was screened with antibodies against both articulins. Two sets of cDNAs were recovered, and evidence from three independent assays confirmed that both sets encoded articulins: (a) Anti-articulin antibodies recognized a high molecular weight beta-galactosidase (beta-gal) fusion protein expressed in bacteria infected with lambda gt11 cDNA clones. (b) Antibodies generated against the bacterially expressed beta-gal fusion protein identified one or the other articulin in Western blots of Euglena proteins. These antibodies also localized to the membrane skeletal region in thin sections of Euglena. (c) Peptide maps of the beta-gal fusion protein were similar to peptide maps of Euglena articulins. From the nucleotide sequence of the two sets of cDNAs an open reading frame for each articulin was deduced. In addition to 37% amino acid identity and overall structural similarity, both articulins exhibited a long core domain consisting of over 30 12-amino acid repeats with the consensus VPVPV--V--. Homology plots comparing the same or different articulins revealed larger, less regular repeats in the core domain that coincided with predicted turns in extended beta-sheets. Outside the core domain a short hydrophobic region containing four seven-amino acid repeats (consensus: APVTYGA) was identified near the carboxy terminus of the 80-kD articulin, but near the amino terminus of the 86-kD articulin. No extensive sequence similarities were found between articulins and other protein sequences in various databanks. We conclude that the two articulins are related members of a new class of membrane cytoskeletal proteins.

scholarly journals Cloning and characterization of a Schistosoma mansoni 1H and 30S clones as two tegumental vaccine candidate antigens.

2003 ◽  
Vol 50 (1) ◽  
pp. 269-278
Author(s):  
Amr M Shabaan ◽  
Magdy M Mohamed ◽  
Mohga S Abdallah ◽  
Hayat M Ibrahim ◽  
Amr M Karim
Keyword(s):  
Amino Acid ◽  
Fusion Protein ◽  
Schistosoma Mansoni ◽  
Molecular Mass ◽  
Vaccine Development ◽  
Complete Sequence ◽  
Cdna Clones ◽  
Western Blots ◽  
Calculated Molecular Mass ◽  
Reading Frame

Two Schistosoma mansoni cDNA clones 30S and 1H were identified by immunoscreening of sporocyst lambdagt11 library and by random sequencing of clones from lambdaZap libraries, respectively. Clone 30S was one of 30 clones identified by an antibody raised against tegument of 3-h schistosomules. The clone was found to encode an 81 amino-acid protein fragment. It was expressed in Escherichia coli as a fusion protein of calculated molecular mass of about 35 kDa with C-terminus of Schistosoma japonicum glutathione-S-transferase (Sj26; about 26 kDa). The recombinant fusion protein was specifically recognized by serum of rabbits immunized with irradiated cercariae. Clone 1H is one of 76 expressed sequence tags derived from an adult worm library. It encodes the complete sequence of a tegumental membrane protein, Sm13. The 104 amino-acid open reading frame encodes a protein with a calculated molecular mass of about 11.9 kDa. Clone 1H was expressed in E. coli as an insoluble fusion protein with Sj26 of about 40 kDa. In Western blots, the fusion protein was recognized by serum from rabbits vaccinated with irradiated cercariae but not by preimmune rabbit sera. The cloning, characterization and expression of those proteins are therefore potentially usefull for vaccine development.

Expression of intermediate filament proteins during development of Xenopus laevis. I. cDNA clones encoding different forms of vimentin

Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 279-298
Author(s):  
H. Herrmann ◽  
B. Fouquet ◽  
W.W. Franke
Keyword(s):  
Amino Acid ◽  
Xenopus Laevis ◽  
Intermediate Filament ◽  
De Novo ◽  
Mesenchymal Cell ◽  
Amino Acid Sequences ◽  
Cytoskeletal Proteins ◽  
Cdna Clones ◽  
Mammalian Development ◽  
Intermediate Filament Proteins

To provide a basis for studies of the expression of genes encoding the diverse kinds of intermediate-filament (IF) proteins during embryogenesis of Xenopus laevis we have isolated and characterized IF protein cDNA clones. Here we report the identification of two types of Xenopus vimentin, Vim1 and Vim4, with their complete amino acid sequences as deduced from the cloned cDNAs, both of which are expressed during early embryogenesis. In addition, we have obtained two further vimentin cDNAs (Vim2 and 3) which are sequence variants of closely related Vim1. The high evolutionary conservation of the amino acid sequences (Vim1: 458 residues; Mr approximately 52,800; Vim4: 463 residues; Mr approximately 53,500) to avian and mammalian vimentin and, to a lesser degree, to desmin from the same and higher vertebrate species, is emphasized, including conserved oligopeptide motifs in their head domains. Using these cDNAs in RNA blot and ribonuclease protection assays of various embryonic stages, we observed a dramatic increase of vimentin RNA at stage 14, in agreement with immunocytochemical results obtained with antibody VIM-3B4. The significance of very weak mRNA signals detected in earlier stages is discussed in relation to negative immunocytochemical results obtained in these stages. The first appearance of vimentin has been localized to a distinct mesenchymal cell layer underlying the neural plate or tube, respectively. The results are discussed in relation to programs of de novo synthesis of other cytoskeletal proteins in amphibian and mammalian development.

Non-neuronal 210 × 10(3) Mr microtubule-associated protein (MAP4) contains a domain homologous to the microtubule-binding domains of neuronal MAP2 and tau

1991 ◽  
Vol 98 (1) ◽  
pp. 27-36
Author(s):  
S.J. Chapin ◽  
J.C. Bulinski
Keyword(s):  
Amino Acid ◽  
Fusion Protein ◽  
Hela Cell ◽  
Fusion Proteins ◽  
Fetal Brain ◽  
Binding Domain ◽  
Amino Acid Sequences ◽  
Cdna Expression Library ◽  
Cdna Clones ◽  
Projection Domain

A polyclonal antiserum raised against a HeLa cell microtubule-associated protein of Mr 210,000 (210 kD MAP or MAP4), an abundant non-neuronal MAP, was used to isolate cDNA clones encoding MAP4 from a human fetal brain lambda gt11 cDNA expression library. The largest of these clones, pMAP4.245, contains an insert of 4.1 kb and encodes a 245 kD beta-galactosidase fusion protein. Evidence that pMAP4.245 encodes MAP4 sequences includes immunoabsorption of MAP4 antibodies with the pMAP4.245 fusion protein, as well as identity of protein sequences obtained from HeLa 210 kD MAP4 with amino acid sequences encoded by pMAP4.245. The MAP4.245 cDNA hybridizes to several large (approximately 6–9 kb) transcripts on Northern blots of HeLa cell RNA. DNA sequencing of overlapping MAP4 cDNA clones revealed a long open reading frame containing a C-terminal region with three imperfect 18-amino acid repeats; this region is homologous to a motif present in the microtubule (MT)-binding domain of two prominent neuronal MAPs, MAP2 and tau. The pMAP4.245 sequence also encoded a series of unrelated repeats, located in the MAP's projection domain, N-terminal to the MT-binding domain. MAP4.245 fusion proteins bound to MTs in vitro, while fusion proteins that contained only the projection domain repeats failed to bind specifically to MTs. Thus, the major human non-neuronal MAP resembles two neuronal MAPs in its MT-binding domain, while most of the molecule has sequences, and presumably functions, distinct from those of the neuronal MAPs.

scholarly journals Molecular analysis of the INCENPs (inner centromere proteins): separate domains are required for association with microtubules during interphase and with the central spindle during anaphase.

1993 ◽  
Vol 123 (2) ◽  
pp. 373-385 ◽  
Author(s):  
A M Mackay ◽  
D M Eckley ◽  
C Chue ◽  
W C Earnshaw
Keyword(s):  
Amino Acid ◽  
Mammalian Cells ◽  
Metaphase Plate ◽  
Class Ii ◽  
Cytoskeletal Proteins ◽  
Cdna Clones ◽  
Coding Region ◽  
Mitotic Chromosomes ◽  
Amino Terminal ◽  
Centromere Proteins

It has recently been proposed that mitotic chromosomes transport certain cytoskeletal proteins to the metaphase plate so that these proteins are able to subsequently participate in the assembly of the anaphase spindle and the cleavage furrow. To understand how such proteins accomplish their dual chromosomal: cytoskeletal role, we have begun a molecular and functional analysis of the inner centromere proteins (INCENPs), founder members of the class of "chromosome passenger proteins". cDNA clones encoding the open reading frames of the two chicken INCENPs were recovered. The predicted proteins, class I INCENP (96,357 D) and class II INCENP (100,931 D) are novel, and differ from each other by the inclusion of a 38-codon insert within the class II coding region. Transient expression of the chicken INCENPs in mammalian cells confirms that the signals and structures required for the transfer of these proteins from chromosomes to cytoskeleton are evolutionarily conserved. Furthermore, these studies reveal that INCENP association with the cytoskeleton is complex. The amino-terminal 42-amino acid residues are required for transfer of the INCENPs from the chromosomes to the mitotic spindle at anaphase, but not for binding of INCENPs to cytoplasmic microtubules. In contrast, an internal 200 amino acid coiled-coil domain was required for association with microtubules, but dispensable for spindle association. These experiments suggest that proteins required for assembly of specialized cytoskeletal structures during mitosis from anaphase onwards might be sequestered in the nucleus throughout interphase to keep them from disrupting the interphase cytoskeleton, and to ensure their correct positioning during mitosis.

scholarly journals Incorporation of the fluorescent amino acid 7-azatryptophan into the core domain 1-47 of hirudin as a probe of hirudin folding and thrombin recognition

2004 ◽  
Vol 13 (6) ◽  
pp. 1489-1502 ◽  
Author(s):  
Vincenzo De Filippis ◽  
Silvia De Boni ◽  
Elisa De Dea ◽  
Daniele Dalzoppo ◽  
Claudio Grandi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Core Domain ◽  
The Core ◽  
Fluorescent Amino Acid

scholarly journals Oligomerization of Hepatitis C Virus Core Protein Is Crucial for Interaction with the Cytoplasmic Domain of E1 Envelope Protein

2006 ◽  
Vol 80 (22) ◽  
pp. 11265-11273 ◽  
Author(s):  
Kousuke Nakai ◽  
Toru Okamoto ◽  
Tomomi Kimura-Someya ◽  
Koji Ishii ◽  
Chang Kweng Lim ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid ◽  
Fusion Protein ◽  
Core Protein ◽  
Type I ◽  
Amino Acid Residues ◽  
Cytoplasmic Loop ◽  
The Core ◽  
Er Membrane

ABSTRACT Hepatitis C virus (HCV) contains two membrane-associated envelope glycoproteins, E1 and E2, which assemble as a heterodimer in the endoplasmic reticulum (ER). In this study, predictive algorithms and genetic analyses of deletion mutants and glycosylation site variants of the E1 glycoprotein were used to suggest that the glycoprotein can adopt two topologies in the ER membrane: the conventional type I membrane topology and a polytopic topology in which the protein spans the ER membrane twice with an intervening cytoplasmic loop (amino acid residues 288 to 360). We also demonstrate that the E1 glycoprotein is able to associate with the HCV core protein, but only upon oligomerization of the core protein in the presence of tRNA to form capsid-like structures. Yeast two-hybrid and immunoprecipitation analyses reveal that oligomerization of the core protein is promoted by amino acid residues 72 to 91 in the core. Furthermore, the association between the E1 glycoprotein and the assembled core can be recapitulated using a fusion protein containing the putative cytoplasmic loop of the E1 glycoprotein. This fusion protein is also able to compete with the intact E1 glycoprotein for binding to the core. Mutagenesis of the cytoplasmic loop of E1 was used to define a region of four amino acids (residues 312 to 315) that is important for interaction with the assembled HCV core. Taken together, our studies suggest that interaction between the self-oligomerized HCV core and the E1 glycoprotein is mediated through the cytoplasmic loop present in a polytopic form of the E1 glycoprotein.

scholarly journals Seven amino acid types suffice to reconstruct the core fold of RNA polymerase

2021 ◽  
Author(s):  
Sota Yagi ◽  
Aditya K. Padhi ◽  
Jelena Vucinic ◽  
Sophie Barbe ◽  
Thomas Schiex ◽  
...  
Keyword(s):  
Amino Acid ◽  
Gene Duplication ◽  
Rna Polymerase ◽  
Translation System ◽  
Primitive Earth ◽  
Evolutionary Pathway ◽  
Core Domain ◽  
The Core ◽  
Beta Barrel ◽  
Early Translation

AbstractThe extant complex proteins must have evolved from ancient short and simple ancestors. Nevertheless, how such prototype proteins emerged on the primitive earth remains enigmatic. The double-psi beta-barrel (DPBB) is one of the oldest protein folds and conserved in various fundamental enzymes, such as the core domain of RNA polymerase. Here, by reverse engineering a modern DPBB domain, we reconstructed its evolutionary pathway started by “interlacing homo- dimerization” of a half-size peptide, followed by gene duplication and fusion. Furthermore, by simplifying the amino acid repertoire of the peptide, we successfully created the DPBB fold with only seven amino acid types (Ala, Asp, Glu, Gly, Lys, Arg, and Val), which can be coded by only GNN and ARR (R = A or G) codons in the modern translation system. Thus, the DPBB fold could have been materialized by the early translation system and genetic code.

Expression of a novel cadherin (EP-cadherin) in unfertilized eggs and early Xenopus embryos

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 315-325 ◽  
Author(s):  
D. Ginsberg ◽  
D. DeSimone ◽  
B. Geiger
Keyword(s):  
Amino Acid ◽  
Fusion Protein ◽  
Western Blot ◽  
Molecular Mass ◽  
Amino Acid Sequences ◽  
The Other ◽  
Relative Molecular Mass ◽  
Cdna Clones ◽  
Cleavage Stage ◽  
Neurula Stage

Two distinct cadherin cDNA clones of Xenopus laevis were isolated from a stage 17 embryo cDNA library. Analysis of the complete deduced amino acid sequences indicated that one of these molecules is closely homologous to chicken and mouse N-cadherin, while the other displays comparable homology to both E- and P-cadherins and was thus denoted EP-cadherin. This molecule has an apparent relative molecular mass of 125 × 10(3) (compared to approx. 138 × 10(3) or approx. 140 × 10(3) of E-cadherin and N-cadherins, respectively). Northern and Western blot analyses indicated that N-cadherin is first expressed at the neurula stage while EP-cadherin is the only cadherin detected in unfertilized eggs and cleavage stage embryos. Immunolabeling of Xenopus eggs with antibodies prepared against a fusion protein, containing a segment of EP-cadherin, indicated that the protein is highly enriched at the periphery of the animal hemisphere. EP-cadherin was also found in A6 epithelial cells derived from Xenopus kidneys, and was apparently localized in the intercellular adherens junctions.

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