68 research outputs found
The primary structures of six human salivary acidic proline-rich proteins (PRP-1, PRP-2, PRP-3, PRP-4, PIF-s and PIF-f)
Type I restriction enzymes and their relatives
Type I restriction enzymes (REases) are large pentameric proteins with separate restriction (R), methylation (M) and DNA sequence-recognition (S) subunits. They were the first REases to be discovered and purified, but unlike the enormously useful Type II REases, they have yet to find a place in the enzymatic toolbox of molecular biologists. Type I enzymes have been difficult to characterize, but this is changing as genome analysis reveals their genes, and methylome analysis reveals their recognition sequences. Several Type I REases have been studied in detail and what has been learned about them invites greater attention. In this article, we discuss aspects of the biochemistry, biology and regulation of Type I REases, and of the mechanisms that bacteriophages and plasmids have evolved to evade them. Type I REases have a remarkable ability to change sequence specificity by domain shuffling and rearrangements. We summarize the classic experiments and observations that led to this discovery, and we discuss how this ability depends on the modular organizations of the enzymes and of their S subunits. Finally, we describe examples of Type II restrictionāmodification systems that have features in common with Type I enzymes, with emphasis on the varied Type IIG enzymes
Study of Structural Relaxation in Amorphous Ni-Pd-P Alloys by Means of X-Ray Diffraction*
A model for DNA binding and enzyme action derived from crystallographic studies of the -adenine-methyltransferase
The crystal structures of the DNA-N6-adenine-methyltransferase MĀ·TaqI, in complexes with the cofactor S-adenosyl-l-methionine (AdoMet) and the competitive inhibitor sinefungin (Sf) show identical folding of the polypeptide chains into two domains. The N-terminal domain carries the cofactor-binding site, the C-terminal domain is thought to be implicated in sequence-specific DNA binding. Model building of the MĀ·TaqI-DNA complex suggests that the adenine to be methylated swings out of the double helix as found previously in the cytosine-C5-MTase HhaI DNA co-crystal structure. A torsion of the methionine moiety of the cofactor is required to bring the methyl group within reach of the swung-out base and allow methyl group transfer
Differential binding of S-adenosylmethionine S-adenosylhomocysteine and Sinefungin to the adenine-specific DNA methyltransferase M.TaqI
Biotin-Avidin Microplate Assay for the Quantitative Analysis of Enzymatic Methylation of DNA by DNA Methyltransferases
Economic evaluation of diagnostic platforms for T790M detection in post EGFR-TKI NSCLC in Brazil.
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