The death-domain fold of the ASC PYRIN domain, presenting a basis for PYRIN/PYRIN recognition.

The PYRIN domain is a conserved sequence motif identified in more than 20 human proteins with putative functions in apoptotic and inflammatory signalling pathways. The three-dimensional structure of the PYRIN domain from human ASC was determined by NMR spectroscopy. The structure determination reveals close structural similarity to death domains, death effector domains, and caspase activation and recruitment domains, although the structural alignment with these other members of the death-domain superfamily differs from previously predicted amino acid sequence alignments. Two highly positively and negatively charged surfaces in the PYRIN domain of ASC result in a strong electrostatic dipole …

Solution Structure of the R3H Domain from Human Sμbp-2

The R3H domain is a conserved sequence motif, identified in over 100 proteins, that is thought to be involved in polynucleotide-binding, including DNA, RNA and single-stranded DNA. In this work the 3D structure of the R3H domain from human Smubp-2 was determined by NMR spectroscopy. It is the first 3D structure determination of an R3H domain. The fold presents a small motif, consisting of a three-stranded antiparallel beta-sheet and two alpha-helices, which is related to the structures of the YhhP protein and the C-terminal domain of the translational initiation factor IF3. The similarities are non-trivial, as the amino acid identities are below 10%. Three conserved basic residues cluster o…

Site-specific Labelling with a Metal Chelator for Protein-structure Refinement

A single free Cys sidechain in the N-terminal domain of the E. coli arginine repressor was covalently derivatized with S-cysteaminyl-EDTA for site-specific attachment of paramagnetic metal ions. The effects of chelated metal ions were monitored with (15)N-HSQC spectra. Complexation of Co(2+), which has a fast relaxing electron spin, resulted in significant pseudocontact shifts, but also in peak doubling which was attributed to the possibility of forming two different stereoisomers of the EDTA-Co(2+) complex. In contrast, complexation of Cu(2+) or Mn(2+), which have slowly relaxing electron spins, did not produce chemical shift changes and yielded self-consistent sets of paramagnetic relaxat…

nmr structure of the pyrin domain of human asc