Modes of binding substrates and their analogues to the enzyme D-xylose isomerase

X-ray diffraction studies of the binding of a series of sugars to D-xylose isomerase are reported at 1.6-1.8 Å resolution. It is shown that there are two directions of binding. A specific binding motif has been identified.

Structure determination of glucose isomerase from Streptomyces murinus at 2.6 Å resolution

The structure is a tetramer with two divalent metal ions per monomer. The structure refinement was performed with the GROMOS program package.

Low-resolution real-space envelopes: the application of the condensing-protocol approach to the ab initio macromolecular phase problem of a variety of examples

A recently reported method [Subbiah (1993). Acta Cryst. D49, 108-119] is applied successfully to obtain crude low-resolution envelopes for five varied and difficult macromolecules. Only Fourier-amplitude data, with no prior phase information, are used to overcome the crystallographic phase problem at very low resolution.

Structure of trypano­thione reductase from Crithidia fasciculata at 2.6 Å resolution; enzyme–NADP interactions at 2.8 Å resolution

The enzyme uses NADPH as a co-factor and is an important target for antitrypanocidal drug design. The structure was solved using molecular replacement and was refined to an R factor of 16.1% with data between 8.0 and 2.6 Å resolution.

Molecular scene analysis: application of a topogical approach to the automated interpretation of protein electron-density maps

A topological analysis method of medium-resolution electron-density maps is described in terms of critical points. A procedure is proposed for the automated recognition of protein secondary structures.

Structure of [2Fe—2S] ferredoxin I from Equisetum arvense at 1.8 Å resolution

Ferredoxin I crystallizes in space group P2₁ with two molecules per asymmetric unit. Refinement by molecular dynamics simulation gave a final R factor of 17% with X-ray data up to 1.8 Å.

Crystallization of biosynthetic arginine de­carboxylase from Escherichia coli

Biosynthetic arginine decarboxylate initiates polyamine synthesis in plants and bacteria and exhibits sequence homology to the eukaryotic ornithine decarboxylases. It has been crystallized in space group P4₁₍₃₎2₁2 with one tetramer per asymmetric unit.

Detection, delineation, measurement and display of cavities in macromolecular structures

Algorithms for detecting cavities in biomacromolecules and for measuring their volumes are described and demonstrated.

Ta₆Br₁₄ is a useful cluster compound for isomorphous replacement in protein crystallography

Experience with the heavy-metal cluster compound Ta₆Br₁₄ in the structure determination of two large proteins is summarized. The cluster compound is a suitable candidate for producing single-site derivatives in large proteins.

Space-group degeneracy in the packing of a non-selfcomplementary Z-DNA hexamer

Crystals of d(CGCACG)·d(CGTGCG) show that similar packing patterns can lead to different space groups.

Initial crystallographic analysis of a recombinant human interleukin-1 receptor antagonist protein

A preliminary structure of an interleukin-l receptor antagonist protein, determined by X-ray crystallographic methods, is reported.

Structure of the ADP complex of the 3-phosphoglycerate kinase from Bacillus stearothermophilus at 1.65 Å

The high-resolution structure of a nucleotide complex of the glycolytic enzyme phosphoglycerate kinase is reported.

Analysis of diffuse scattering from yeast initiator tRNA crystals

An encouraging step forward in the ability to use X-ray diffuse scattering information is presented. Analysis of this scattering from yeast initiator tRNA crystals reveals substantial disorder in the biochemically relevant anticodon arm where atomic displacements are locally correlated between neighbouring base pairs but quite uncoupled from the more rigid remainder of the molecule.

New crystal forms of a μ-class gluta­thione S-transferase from rat liver

Two new crystal forms of glutathione 5-transferase 3-3 have been obtained. The structures of these new crystal forms have been determined and their crystal packing environments have been compared.

Crystallization and preliminary X-ray analysis of a lipase from Chromobacterium viscosum

A lipase from Chromobocteriun viscosum has been purified to homogeneity and crystallized in a form suitable for X-ray diffraction analysis. The crystals diffract to a resolution of 2.2 Å and the structure solution by multiple isomorphous replacement is underway.

A designed mutant of the enzyme gluta­thione reductase shortens the crystallization time by a factor of forty

A designed mutant of the enzyme glutathione reductase, consisting of two point mutations, shortens the crystallization time by a factor of forty, most probably by facilitating nucleation.

Crystallization and preliminary investigation of xylose isomerase from Bacillus coagulans

Two different crystal forms have been obtained, one suitable for X-ray analysis.

Crystallization and preliminary X-ray diffraction analysis of tetra-heme cytochrome c₃ from sulfate- and nitrate-reducing Desulfovibrio desulfuricans ATCC 27774

Crystallization of tetra-heme cytochrome c from Desulfovibrio desulfuricans ATCC 27774 in space group P6₁22, a = b = 61.84(4), c = 109.7 (2) Å, led to X-ray data to 1.75 Å resolution, R_merge(I) = 5.3%. A molecular replacement solution was obtained with D. vulgaris cytochrome c (43% homology).

Refined structure of cadmium-substituted concanavalin A at 2.0 Å resolution. Erratum

Correction to Acta Cryst. (1993). D49, 561-571.