Showing papers in "Structure in 1996"

TL;DR: The unveiling of similarities and differences in the architecture of these proteins may provide valuable insight into the efficient energy transfer mechanisms of bacterial photosynthesis and place all oscillator strength into energetically low lying, thermally accessible exciton states.

TL;DR: Firefly luciferase is the first member of a superfamily of homologous enzymes, which includes acyl-coenzyme A ligases and peptide synthetases, to have its structure characterized.

TL;DR: The errors that can be introduced into a protein model during model building and refinement vary tremendously in their importance and severity, and for a structure built into an experimental map, the main ones are limited resolution and poorly phased diffraction data.

TL;DR: The refined structure of the Zif268 protein-DNA complex confirms all the basic features of the previous model and allows us to focus on some critical details at the protein- DNA interface, and helps explain the roles of several acidic residues located in the recognition helices.

TL;DR: The histidine-cobalt distance is very long, suggesting that the enzyme positions the histidine in order to weaken the metal-carbon bond of the cofactor and favour the formation of the initial radical species.

TL;DR: The comparison of two very different conformations of the same polypeptide chain revealed kinematic details of the catalytic cycle and indicated that there exists an energetic counterweight compensating the substrate binding energy required for specificity.

TL;DR: The ability to time-resolve the structural features mentioned above makes SDSL a powerful approach for exploring the evolution of structure on the millisecond time scale and is anticipated to have future applications to the study of protein folding both in solution and in chaperone-mediated systems.

TL;DR: It has been suggested that a reduced pKa in the first cysteine of the active-site sequence is important for modulation of the redox potential in thioredoxin, and may provide a mechanism for regulation of the protein, or a means of sensing oxidative stress.

TL;DR: GJK thanks Dr T Alwyn Jones for many stimulating discussion concerning model quality, validation and the free R value, and Dr Randy J Read for suggesting the test with a backward-traced model containing NCS.

TL;DR: This work suggests that amyloid fibrils have a novel molecular structure consisting of s sheets extended in regular helical twists along the length of the fibre, which implies that the polypeptide chains in the fibers are hydrogen-bonded together along the entire length ofthe fibers, thereby accounting for their great stability.

TL;DR: Structural analysis indicates that affinity for the penta-coordinated zinc can be modulated by neighboring residues, perhaps explaining the absence of the second zinc in the B. cereus structure.

TL;DR: It is suggested that titin Ig domains in the I-band function as extensible components of muscle elasticity by stretching the hinge regions.

TL;DR: It is proposed that the contact between five-coordinated and six- Coordinated pentamers may help to generate a six-pentamer nucleus, with which further pentamerers can assemble to generate the complete particle.

TL;DR: Comparison of the unliganded RT structures with the DNA-bound RT and the NNRTI-boundRT structures reveals that the p66 thumb subdomain can exhibit two different upright conformations, which may account for the inhibition of polymerization and the alteration of the cleavage specificity of RNase H by NN RTI binding.

TL;DR: A two-base mechanism by which the histidine and aspartic acid together catalyze dehydration and isomerization reactions is consistent with the active-site structure, revealing features of predictive value for another enzyme, FabZ, which may be the non-specific dehydratase involved in elongation of fatty acyl chains.

TL;DR: The structure of huIFN-alpha 2b provides an accurate model for analysis of the > 15 related type 1 interferon molecules and identifies protein surfaces that appear to be important in receptor activation.

TL;DR: The high-resolution structure supports the proposed coordination pattern involving histidine ligands and provides a basis for a detailed analysis of the spectroscopic and electrochemical properties of the 'Rieske' [2Fe-2S] cluster.

TL;DR: Evidence is provided that energy transfer between the B800 and B850 bacteriochlorophylls is largely via Förster induced dipole-dipole resonance, and how clever and efficient the energy transfer mechanism has become, with singlet-singlet excitation being passed smoothly down the spectral gradient to the reaction centre is illustrated.

TL;DR: Carboxylate shifts are often important for car boxylate coordinated metal clusters; they allow the metals to achieve different coordination modes in redox reactions, in the case of reduced R2 these carboxylates shifts allow the formation of accessible reaction sites for dioxygen.

TL;DR: This is the first complete structure of a class III peroxidase and as such should serve as a model for other class III enzymes including the much-studied horseradish per oxidase.

TL;DR: The features of the observed metal-binding sites expand the known repertoire of ligand-binding motifs in RNA, and suggest that some of the conserved tandem G.U base pairs in ribosomal RNAs are magnesium- binding sites.

TL;DR: EF-Tu undergoes major conformational changes upon GTP hydrolysis, involving an unwinding of a small helix and the formation of a beta hairpin structure in the effector region.

TL;DR: A model for regulation is proposed in which the Ca(2+)-bound RD is a rigid structure, and transient flexibility of the Ca-free RD allows the myosin heads to make stabilizing intramolecular linkage which shut off the motor.

TL;DR: There is considerable structural homology between PSAO and ECAO, and a combination of evidence from both structures indicates that the TPQ side chain is sufficiently flexible to permit the aromatic grouf to rotate about the Cbeta-Cgamma bond, and to move between bonding and non-bonding positions with respect to the Cu atom.

TL;DR: The present structure reveals the mode of binding of the natural substrate UDP-GlcNAc and of the drug fosfomycin, and provides information on the residues involved in catalysis, and should aid the design of inhibitors which would interfere with enzyme-catalyzed reactions in the early stage of the bacterial cell wall biosynthesis.

TL;DR: This analysis indicates that there are at least thirteen myosin classes, with remarkably poor overall conservation at the site thought to be involved in actin binding, but several highly conserved residues have been identified that may be functionally important.

TL;DR: From the structure of the complex of the enzyme with the substrate and cofactor of the oxidation reaction, the orientation of the substrates for the reduction reaction can be deduced with confidence.

TL;DR: The cofactor preferences exhibited by the enzymes of the SDR family are mainly determined by the electrostatic environment surrounding the 2'-hydroxyl (or phosphate) group of the adenosine ribose moiety of NADH (or NADPH).

TL;DR: LA's proposed interaction site for the catalytic component of the lactose synthase complex is primarily located in the flexible C-terminal portion of the molecule, which implies that conformational adjustments may be important for the formation and function of lactOSE synthase.

TL;DR: In this paper, the crystal structure of small RNA bacteriophage Qβ was determined at 3.5 a resolution and it was shown that the capsid is stabilized by disulfide bonds on each side of the flexible loops that are situated around the fivefold and quasi-sixfold axes.