Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.31.1 (micrococcal nuclease)
 2,818 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The three-dimensional structure of the antibody N10 Fab fragment complexed with staphylococcal nuclease (SNase) has been determined to 2.9 A resolution. Eighteen residues from six complementarity-determining regions (CDR) recognize an epitope of five distinct SNase segments with a total of 17 residues. The overall shape of the antibody-antigen interface is U-shaped rather than the more or less rectangular interface seen in other antibody-protein antigen interfaces. Despite the U-shaped interface, the amount of surface buried in the complex, 828 A2 for SNase and 793 A2 for N10, is typical of antibody-protein antigen complexes. Contributing to the shape of the interface is the shortest antibody heavy chain-CDR3 loop reported to date, which probably allows access of bulk solvent in the center of the "U" interface. Another unusual feature of the N10 antibody is the 15 residue antibody light chain-CDR1, a length seen in only three other reported antibodies. Antibody light chain-CDR1 displays a previously unobserved conformation in its distal portion. Finally, although some of the movement observed in the antibody-bound SNase may be due to crystal contacts, it is clear that some side-chain rearrangements are the result of antigen-antibody interaction.
 ...
PMID:The crystal structure of the antibody N10-staphylococcal nuclease complex at 2.9 A resolution. 747 34

Chromatin regulates many key processes in the nucleus by controlling access to the underlying DNA. SNF2-like factors are ATP-driven enzymes that play key roles in the dynamics of chromatin by remodelling nucleosomes and other nucleoprotein complexes. Even simple eukaryotes such as yeast contain members of several subfamilies of SNF2-like factors. The FUN30/ETL1 subfamily of SNF2 remodellers is conserved from yeasts to humans, but is poorly characterized. We show that the deletion of FUN30 leads to sensitivity to the topoisomerase I poison camptothecin and to severe cell cycle progression defects when the Orc5 subunit is mutated. We demonstrate a role of FUN30 in promoting silencing in the heterochromatin-like mating type locus HMR, telomeres and the rDNA repeats. Chromatin immunoprecipitation experiments demonstrate that Fun30 binds at the boundary element of the silent HMR and within the silent HMR. Mapping of nucleosomes in vivo using micrococcal nuclease demonstrates that deletion of FUN30 leads to changes of the chromatin structure at the boundary element. A point mutation in the ATP-binding site abrogates the silencing function of Fun30 as well as its toxicity upon overexpression, indicating that the ATPase activity is essential for these roles of Fun30. We identify by amino acid sequence analysis a putative CUE motif as a feature of FUN30/ETL1 factors and show that this motif assists Fun30 activity. Our work suggests that Fun30 is directly involved in silencing by regulating the chromatin structure within or around silent loci.
 ...
PMID:The SNF2-family member Fun30 promotes gene silencing in heterochromatic loci. 1995 93