Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “local structure”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources
PubMed1976

The fine structural localization of peroxidase activity in goblet cells of the conjunctival epithelium of rats.

Cytochemical investigation of peroxidase was made on the conjunctival goblet cells, using the diaminobenzidine method. Many goblet cells in the conjunctiva demonstrated this reaction. The reaction was present in secretory granules as well as in the perinuclear cisterna, the rough endoplasmic reticulum, several Golgi saccules and adjacent small smooth-surfaced vesicles, and condensing vacuoles. Each secretory granule within a goblet cell showed a different degree of reaction, hence it is concluded that some goblet cells probably produce both mucous substance and peroxidase in one cell. The mode of production of peroxidase in goblet cells is concluded to be similar to that of secretory proteins in pancreatic exocrine cells. The enzyme, together with thiocyanate and endogenous hydrogen peroxide, is thought to serve as an anti-infectious agent in tears.

Amitrole↗
PubMed2004

[Structure, localization and characterization of lipocalin-type prostaglandin D synthase].

Lipocalin-type prostaglandin D synthase (L-PGDS), an N-glycosylated dual functional monomeric protein, acts as a PGD2-producing enzyme and also as a lipophilic ligand-binding protein. L-PGDS is localized in the central nervous system, male genital organs of various mammals and in the human and monkey heart, and secreted into the cerebrospinal fluid, seminal plasma and blood plasma. The L-PGDS concentrations in these body fluids are useful for the diagnosis of several neurological disorders, dysfunction of sperm formation, cardiovascular and renal diseases.

Amino Acid Sequence↗
PubMed1992

The human T cell transcription factor-1 gene. Structure, localization, and promoter characterization.

We have recently isolated cDNA clones representing four alternative splice forms of a T cell-specific transcription factor, TCF-1. Here we report the characterization of the human gene encoding this factor. The TCF-1 gene is contained in 10 exons including an untranslated first exon. The DNA-binding high mobility group (HMG) box of TCF-1 is encoded by the closely spaced exons VI and VII. Differential splicing involves an alternative exon (IX) and three splice acceptor sites in exon X. Based on comparison of sequence and on the placement of an alternative exon, TCF-1 appears closely related to the recently characterized HMG box transcription factor TCF-1 alpha/LEF. In particular, the HMG boxes encoded by the two TCF genes are virtually identical. The TCF-1 gene resides on chromosome 5 band q31.1. The TCF-1 promoter coincides with a CpG island. As determined by chloramphenicol acetyltransferase analysis, the promoter is preferentially active in T cells. The promoter does not contain TCF-1/TCF-1 alpha binding sites and is therefore not autoregulated. This observation implies the existence of yet uncharacterized T cell transcription factors that are active during early T cell differentiation.

Amino Acid Sequence↗
PubMed1991

[High mobility group proteins: structure, localization, function].

High motility group proteins (HMG) are extracted by 5% HCIO4 and 0.35 M NaCl and are characterized by low molecular mass and a high content of acidic and basic amino acids. There is evidence that HMG are involved in the formation of transcriptionally active chromatin.

Amino Acids↗
PubMed1991

Myc protein structure: localization of DNA-binding and protein dimerization domains.

Wildtype and mutant v-Myc proteins were overexpressed in Escherichia coli using the T7 RNA polymerase system, and the in vitro DNA-binding activities of partially or highly purified proteins were analysed by native DNA-cellulose chromatography. For the construction of the expression plasmids, cloned proviral DNA from wildtype MC29 or from its spontaneous deletion mutant Q10C was used, the latter lacking internal v-myc sequences. Both the wildtype (p59) and the mutant (p42) recombinant protein contain at their amino termini 12 amino acids encoded by the vector, followed by 11 gag amino acids and 9 amino acids encoded by v-myc sequences derived from noncoding c-myc sequences. In addition, p59 contains 416 amino acids encoded by v-myc sequences derived from the complete chicken c-myc coding region, whereas p42 lacks 120 amino acids from the central region of the Myc protein including the highly acidic domain. Two additional proteins were engineered which contain the first 309 (p53) or the last 107 (p16) amino acids, respectively, of the Myc protein sequence in addition to vector-encoded amino acids. The p16 protein represents the carboxyl terminus of the Myc protein sequence containing both a muscle determination gene (MyoD1) homology region, including a basic motif and an amphipathic helix-loop-helix motif, and a leucine heptad repeat. All proteins, except p53 which lacks the carboxyl-terminal Myc protein sequences, bound to native DNA-cellulose and were eluted with 200-500 mM NaCl. Based on the DNA-binding activities of recombinant or spontaneous mutant v-Myc proteins extracted from bacterial or from transformed avian cells, we conclude that the DNA-binding domain of avian Myc proteins is confined within the last 86 carboxyl-terminal amino acids. The same region is also shown to be necessary and sufficient for Myc protein dimerization. This 86-amino acid region essentially encompasses a putative basic DNA contact surface and a tandem array of two presumed protein dimerization motifs, helix-loop-helix and leucine repeat.

Amino Acid Sequence↗
PubMed1990

Ubiquitin extension proteins of Arabidopsis thaliana. Structure, localization, and expression of their promoters in transgenic tobacco.

The highly conserved protein ubiquitin is synthesized in eukaryotes as two types of protein fusions from which active ubiquitin is derived by proteolytic processing. We report here the isolation and characterization of multiple genes from one type that encode ubiquitin extension proteins from the higher plant, Arabidopsis thaliana (L.). Two genes with 90% nucleotide identity in their exons encode ubiquitin and identical 52-amino acid (aa) extension proteins with 85 and 79% aa identity to 52-aa extension proteins from humans and yeast, respectively. Two other genes with 90% nucleotide identity encode ubiquitin and 81-aa extension proteins that differ by 4 amino acids from each other and are approximately 70% identical to the 76- and the 80-aa extension proteins from yeast and humans, respectively. Antibodies recognizing the 52- and 81-aa Arabidopsis extension proteins identify them as constituents of ribosomes. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the 52- and 81-aa extension proteins migrate at 6.8 and 11.5 kDa, respectively, and neither cross-reacts with anti-ubiquitin antibodies, indicating that extension proteins are cleaved from ubiquitin following translation. Ubiquitin extension protein genes encode the smallest transcript size class of ubiquitin mRNAs in Arabidopsis. The 5'-flanking regions of both UBQ1 and UBQ6, genes representative of the both extension proteins, direct the expression of readily detectable levels of the marker enzyme beta-glucuronidase in transgenic tobacco, suggesting the utility of these promoters for expression of foreign genes in higher plants.

Amino Acid Sequence↗
PubMed1990

A fine structural localization of the non-specific cholinesterase activity in glomerular nerve formations (endings).

Snout glabrous skin (rhinarium) of the cat is innervated not only by typical simple lamellar corpuscles but also glomerular formations. In contrast to simple lamellar corpuscles, glomerular nerve formations are located away the dermal papillae. In cross sections, glomerular nerve formation consists of several axonal profiles enveloped by 1-2 cytoplasmic lamellae of Schwann cells. The space among them is filled by collagenous microfibrils and the basal lamina-like material. Capsule was composed from fibroblast-like cells without definite basal lamina. An electron-dense reaction product due to non-specific cholinesterase activity was associated with Schwann cells and their processes surrounding unmyelinated terminal portion of the sensory axons. Abundant reaction product was bound to the collagenous microfibrils and was deposited in extracellular matrix between Schwann cell processes. These results are further evidence for the presence of the non-specific cholinesterase molecules as integral component of the extracellular matrix in sensory corpuscles. On the basis of histochemical study two possible explanation are considered for functional involving of this enzyme in sensory nerve formations.

Animals↗