scholarly journals Identification and properties of the Deinococcus grandis and Deinococcus proteolyticus single-stranded DNA binding proteins (SSB).

2007 ◽  
Vol 54 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Paweł Filipkowski ◽  
Józef Kur
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Amino Acid Sequence ◽  
Deinococcus Radiodurans ◽  
Thermus Thermophilus ◽  
Biochemical Properties ◽  
Thermus Aquaticus ◽  
Single Stranded Dna ◽  
Calculated Molecular Mass

To study the biochemical properties of SSB's from Deinococcus grandis (DgrSSB) and Deinococcus proteolyticus (DprSSB), we have cloned the ssb genes obtained by PCR and have developed Escherichia coli overexpression systems. The genes consist of an open reading frame of 891 (DgrSSB) and 876 (DprSSB) nucleotides encoding proteins of 296 and 291 amino acids with a calculated molecular mass of 32.29 and 31.33 kDa, respectively. The amino-acid sequence of DgrSSB exhibits 45%, 44% and 82% identity and the amino-acid sequence of DprSSB reveals 43%, 43% and 69% identity with Thermus aquaticus (TaqSSB), Thermus thermophilus (TthSSB) and Deinococcus radiodurans SSBs, respectively. We show that DgrSSB and DprSSB are similar to Thermus/Deinococcus SSBs in their biochemical properties. They are functional as homodimers, with each monomer encoding two single-stranded DNA binding domains (OB-folds). In fluorescence titrations with poly(dT), both proteins bind single-stranded DNA with a binding site size of about 33 nt per homodimer. In a complementation assay in E. coli, DgrSSB and DprSSB took over the in vivo function of EcoSSB. Thermostability with half-lives of about 1 min at 65-67.5 degrees C make DgrSSB and DprSSB similar to the known SSB of Deinococcus radiodurans (DraSSB).

Thermus aquaticus ATCC 33923 Amylomaltase Gene Cloning and Expression and Enzyme Characterization: Production of Cycloamylose

1999 ◽  
Vol 65 (3) ◽  
pp. 910-915 ◽  
Author(s):  
Yoshinobu Terada ◽  
Kazutoshi Fujii ◽  
Takeshi Takaha ◽  
Shigetaka Okada
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Molecular Mass ◽  
Minimum Degree ◽  
Cloning And Expression ◽  
Gene Cloning And Expression ◽  
Thermus Aquaticus ◽  
Average Molecular Mass ◽  
Calculated Molecular Mass ◽  
E Coli

ABSTRACT The amylomaltase gene of the thermophilic bacterium Thermus aquaticus ATCC 33923 was cloned and sequenced. The open reading frame of this gene consisted of 1,503 nucleotides and encoded a polypeptide that was 500 amino acids long and had a calculated molecular mass of 57,221 Da. The deduced amino acid sequence of the amylomaltase exhibited a high level of homology with the amino acid sequence of potato disproportionating enzyme (D-enzyme) (41%) but a low level of homology with the amino acid sequence of theEscherichia coli amylomaltase (19%). The amylomaltase gene was overexpressed in E. coli, and the enzyme was purified. This enzyme exhibited maximum activity at 75°C in a 10-min reaction with maltotriose and was stable at temperatures up to 85°C. When the enzyme acted on amylose, it catalyzed an intramolecular transglycosylation (cyclization) reaction which produced cyclic α-1,4-glucan (cycloamylose), like potato D-enzyme. The yield of cycloamylose produced from synthetic amylose with an average molecular mass of 110 kDa was 84%. However, the minimum degree of polymerization (DP) of the cycloamylose produced by T. aquaticus enzyme was 22, whereas the minimum DP of the cycloamylose produced by potato D-enzyme was 17. The T. aquaticus enzyme also catalyzed intermolecular transglycosylation of maltooligosaccharides. A detailed analysis of the activity of T. aquaticus ATCC 33923 amylomaltase with maltooligosaccharides indicated that the catalytic properties of this enzyme differ from those of E. coliamylomaltase and the plant D-enzyme.

Genetic Analysis of Yeast RPA1 Reveals Its Multiple Functions in DNA Metabolism

Genetics ◽  
1998 ◽  
Vol 148 (3) ◽  
pp. 989-1005 ◽  
Author(s):  
Keiko Umezu ◽  
Neal Sugawara ◽  
Clark Chen ◽  
James E Haber ◽  
Richard D Kolodner
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Protein A ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Physical Analysis ◽  
Single Stranded Dna ◽  
Temperature Sensitive Mutants

Abstract Replication protein A (RPA) is a single-stranded DNA-binding protein identified as an essential factor for SV40 DNA replication in vitro. To understand the in vivo functions of RPA, we mutagenized the Saccharomyces cerevisiae RFA1 gene and identified 19 ultraviolet light (UV) irradiation- and methyl methane sulfonate (MMS)-sensitive mutants and 5 temperature-sensitive mutants. The UV- and MMS-sensitive mutants showed up to 104 to 105 times increased sensitivity to these agents. Some of the UV- and MMS-sensitive mutants were killed by an HO-induced double-strand break at MAT. Physical analysis of recombination in one UV- and MMS-sensitive rfa1 mutant demonstrated that it was defective for mating type switching and single-strand annealing recombination. Two temperature-sensitive mutants were characterized in detail, and at the restrictive temperature were found to have an arrest phenotype and DNA content indicative of incomplete DNA replication. DNA sequence analysis indicated that most of the mutations altered amino acids that were conserved between yeast, human, and Xenopus RPA1. Taken together, we conclude that RPA1 has multiple roles in vivo and functions in DNA replication, repair, and recombination, like the single-stranded DNA-binding proteins of bacteria and phages.

The lymphoid transcription factor LyF-1 is encoded by specific, alternatively spliced mRNAs derived from the Ikaros gene

1994 ◽  
Vol 14 (11) ◽  
pp. 7111-7123
Author(s):  
K Hahm ◽  
P Ernst ◽  
K Lo ◽  
G S Kim ◽  
C Turck ◽  
...  
Keyword(s):  
Amino Acid ◽  
T Cell ◽  
Dna Binding ◽  
Amino Acid Sequence ◽  
Zinc Finger ◽  
T Cell Development ◽  
Cell Development ◽  
Control Element ◽  
Early Stages ◽  
Alternatively Spliced

The lymphocyte-specific DNA-binding protein LyF-1 interacts with a critical control element in the terminal deoxynucleotidyltransferase (TdT) promoter as well as with the promoters for other genes expressed during early stages of B- and T-cell development. We have purified LyF-1 and have obtained a partial amino acid sequence from proteolytic peptides. The amino acid sequence suggests that LyF-1 is a zinc finger protein encoded by the Ikaros gene, which previously was implicated in T-cell development. Recombinant Ikaros expressed in Escherichia coli bound to the TdT promoter, and antisera directed against the recombinant protein specifically blocked the DNA-binding activity of LyF-1 in crude extracts. Further analysis revealed that at least six distinct mRNAs are derived from the Ikaros/LyF-1 gene by alternative splicing. Only two of the isoforms possess the N-terminal zinc finger domain that is necessary and sufficient for TdT promoter binding. Although both of these isoforms bound to similar sequences in the TdT, lambda 5, VpreB, and lck promoters, one isoform contains an additional zinc finger that resulted in altered recognition of some binding sites. At least four of the Ikaros/LyF-1 isoforms were detectable in extracts from B- and T-cell lines, with the relative amounts of the isoforms varying considerably. These data reveal that the LyF-1 protein is encoded by specific mRNAs derived from the alternatively-spliced Ikaros gene, suggesting that this gene may be important for the early stages of both B- and T-lymphocyte development.

Biochemical and genetic characterization of a yeast TFIID mutant that alters transcription in vivo and DNA binding in vitro

1992 ◽  
Vol 12 (5) ◽  
pp. 2372-2382
Author(s):  
K M Arndt ◽  
S L Ricupero ◽  
D M Eisenmann ◽  
F Winston
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Direct Repeat ◽  
Single Amino Acid ◽  
Wild Type ◽  
Dna Binding Specificity ◽  
Selection For

A mutation in the gene that encodes Saccharomyces cerevisiae TFIID (SPT15), which was isolated in a selection for mutations that alter transcription in vivo, changes a single amino acid in a highly conserved region of the second direct repeat in TFIID. Among eight independent spt15 mutations, seven cause this same amino acid change, Leu-205 to Phe. The mutant TFIID protein (L205F) binds with greater affinity than that of wild-type TFIID to at least two nonconsensus TATA sites in vitro, showing that the mutant protein has altered DNA binding specificity. Site-directed mutations that change Leu-205 to five different amino acids cause five different phenotypes, demonstrating the importance of this amino acid in vivo. Virtually identical phenotypes were observed when the same amino acid changes were made at the analogous position, Leu-114, in the first repeat of TFIID. Analysis of these mutations and additional mutations in the most conserved regions of the repeats, in conjunction with our DNA binding results, suggests that these regions of the repeats play equivalent roles in TFIID function, possibly in TATA box recognition.

Conserved DNA binding and self-association domains of the Drosophila zeste protein

1992 ◽  
Vol 12 (2) ◽  
pp. 598-608
Author(s):  
J D Chen ◽  
C S Chan ◽  
V Pirrotta
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Amino Acid Sequence ◽  
Coiled Coil ◽  
Helical Structure ◽  
Binding Activity ◽  
Binding Domain ◽  
Drosophila Virilis ◽  
Predicted Amino Acid Sequence ◽  
Dna Binding Domain

The zeste gene product is involved in two types of genetic effects dependent on chromosome pairing: transvection and the zeste-white interaction. Comparison of the predicted amino acid sequence with that of the Drosophila virilis gene shows that several blocks of amino acid sequence have been very highly conserved. One of these regions corresponds to the DNA binding domain. Site-directed mutations in this region indicate that a sequence resembling that of the homeodomain DNA recognition helix is essential for DNA binding activity. The integrity of an amphipathic helical region is also essential for binding activity and is likely to be responsible for dimerization of the DNA binding domain. Another very strongly conserved domain of zeste is the C-terminal region, predicted to form a long helical structure with two sets of heptad repeats that constitute two long hydrophobic ridges at opposite ends and on opposite faces of the helix. We show that this domain is responsible for the extensive aggregation properties of zeste that are required for its role in transvection phenomena. A model is proposed according to which the hydrophobic ridges induce the formation of open-ended coiled-coil structures holding together many hundreds of zeste molecules and possibly anchoring these complexes to other nuclear structures.

Association of the brain anion exchanger, AE3, with the repeat domain of ankyrin

1993 ◽  
Vol 105 (4) ◽  
pp. 1137-1142 ◽  
Author(s):  
C.W. Morgans ◽  
R.R. Kopito
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Anion Exchanger ◽  
Deletion Mutant ◽  
Tandem Repeats ◽  
Structural Homology ◽  
Terminal Domain ◽  
Repeat Domain ◽  
The Brain

The 89 kDa NH2-terminal domain of erythrocyte ankyrin is composed almost entirely of 22 tandem repeats of a 33 amino acid sequence and constitutes the binding site for the cytoplasmic NH2-terminal domain of the erythrocyte anion exchanger, AE1. We have developed an assay to evaluate the in vivo interaction between a fragment of ankyrin corresponding to this domain (ANK90) and two non-erythroid anion exchangers, AE2 and AE3, that share considerable structural homology with AE1. Association was assessed by co-immunoprecipitation of ANK90-anion exchanger complexes from detergent extracts of cells cotransfected with plasmids encoding the ankyrin fragment and the anion exchanger or mutants thereof. ANK90 was co-immunoprecipitated with AE1 but not with an AE1 deletion mutant lacking the cytoplasmic NH2-terminal domain. Using this assay, we show that the brain anion exchanger AE3, but not the closely related homologue, AE2, is capable of binding to ankyrin.

scholarly journals Residues in the Swi5 Zinc Finger Protein That Mediate Cooperative DNA Binding with the Pho2 Homeodomain Protein

1998 ◽  
Vol 18 (11) ◽  
pp. 6436-6446 ◽  
Author(s):  
Leena T. Bhoite ◽  
David J. Stillman
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Zinc Finger ◽  
Transcriptional Activation ◽  
Binding Proteins ◽  
Zinc Finger Protein ◽  
Interaction Analysis ◽  
Dna Binding Proteins ◽  
Two Hybrid

ABSTRACT The Swi5 zinc finger and the Pho2 homeodomain DNA-binding proteins bind cooperatively to the HO promoter.Pho2 (also known as Bas2 or Grf10) activates transcription of diverse genes, acting with multiple distinct DNA-binding proteins. We have performed a genetic screen to identify amino acid residues in Swi5 that are required for synergistic transcriptional activation of a reporter construct in vivo. Nine unique amino acid substitutions within a 24-amino-acid region of Swi5, upstream of the DNA-binding domain, reduce expression of promoters that require both Swi5 and Pho2 for activation. In vitro DNA binding experiments show that the mutant Swi5 proteins bind DNA normally, but some mutant Swi5 proteins (resulting from SWI5* mutations) show reduced cooperative DNA binding with Pho2. In vivo experiments show that these SWI5* mutations sharply reduce expression of promoters that require both SWI5 and PHO2, while expression of promoters that require SWI5 but arePHO2 independent is largely unaffected. This suggests that these SWI5* mutations do not affect the ability of Swi5 to bind DNA or activate transcription but specifically affect the region of Swi5 required for interaction with Pho2. Two-hybrid experiments show that amino acids 471 to 513 of Swi5 are necessary and sufficient for interaction with Pho2 and that the SWI5* point mutations cause a severe reduction in this two-hybrid interaction. Analysis of promoter activation by these mutants suggests that this small region of Swi5 has at least two distinct functions, conferring specificity for activation of the HO promoter and for interaction with Pho2.

Sign in / Sign up

Export Citation Format

Share Document