Structure of bacteriophage T4 RNase H, a 5' to 3' RNA-DNA and DNA-DNA exonuclease with sequence similarity to the RAD2 family of eukaryotic proteins
Article Abstract:
Crystal structure studies of bacteriophage T4 RNase H in the presence of Mg2+ and absence of nucleic acids reveal the presence of a central groove similar to that present in DNA-metabolizing enzymes and DNA-binding proteins. The groove divides a large subdomain on the right and a small subdomain on the left. Two magnesium ions are bound in a cluster of conserved acidic residues at the base of the groove to form the active site. The structure of the enzyme furnishes a basis for understanding the structures of other RAD2 nuclease family proteins.
Publication Name: Cell
Subject: Biological sciences
ISSN: 0092-8674
Year: 1996
User Contributions:
Comment about this article or add new information about this topic:
A novel divalent cation-binding site in the A domain of the beta-2 integrin CR3 (CD11b/CD18) is essential for ligand binding
Article Abstract:
The identification of recombinant peptide CD11b, a novel cation-binding site in the A-domain of the beta-2 integrin complement receptor type 3 (CR3), is reported. The peptide bound Mn2+ with high affinity. Other divalent cations competed effectively for Mn2+ binding, while amino acid substitutions at specific sites removed Mn2+ binding properties. These results indicate a previously unknown metal-binding site in the A domain of CR3, and suggest a potential direction for designer drugs against CR3-mediated inflammatory reactions.
Publication Name: Cell
Subject: Biological sciences
ISSN: 0092-8674
Year: 1993
User Contributions:
Comment about this article or add new information about this topic:
Crystal structure of the A Domain from the alpha subunit of integrin CR3 (CD11b/CD18)
Article Abstract:
A crystallographic evaluation of the A domain of CR3 integrin helps study its preferential adhesive interactions at the molecular level. A classic alpha/beta Rossmann fold characterizes the domain, which has a Mg2+ coordination site at its surface. The glutamate side chain from another A domain molecule forms a coordinating ligand at this site, which forms the general metal ion-dependent adhesion site (MIDAS) for protein ligand binding. A MIDAS motif inside an altered A domain characterizes the beta subunits of integrins.
Publication Name: Cell
Subject: Biological sciences
ISSN: 0092-8674
Year: 1995
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: The dspA gene product of the cyanobacterium Synechocystis sp. strain PCC 6803 influences sensitivity to chemically different growth inhibitors and has amino acid similarity to histidine protein kinases
- Abstracts: Regulation of the appearance of division asynchrony and microtubule-dependent chromosome cycles in Xenopus laevis embryos
- Abstracts: 2.0 angstrom crystal structure of a four-domain segment of human fibronectin encompassing the RGD loop and synergy region
- Abstracts: GcvA, a LysR-type transcriptional regulator protein, activates expression of the cloned Citrobacter freundii ampC beta-lactamase gene in Escherichia coli: cross-talk between DNA-binding proteins
- Abstracts: Hedgehog and beyond. Negative feedback mechanisms and their roles during pattern formation. Mammalian and Drosophila blood: JAK of all trades?