Using genetic algorithms for solving heavy-atom sites

A novel procedure has been developed using genetic algorithms to search for heavy-atom sites in a difference Patterson function.

Enhancement of the method of molecular replacement by incorporation of known structural information

Methods are proposed whereby information from one part of a crystal structure that has been determined can be used to help determine the structure of the remainder. Applications to mutants of phage T4 lysozyme are described.

Crystallization of wild-type and mutant ferricytochromes c at low ionic strength: seeding technique and X-ray diffraction analysis

The ferricytochromes c of horse, rat and of two rat-protein mutants, crystallized at low ionic strength from a solution of PEG, have space group P2₁2₁2₁. A novel application of macro-seeding was employed.

Core tracing: depicting connections between features in electron density

Paths of high density are traced by lines connecting peaks to passes. Picture complexity approximates that of α-carbon models.

Accuracy and precision in protein crystal structure analysis: two independent refinements of the structure of poplar plastocyanin at 173 K

The structure of a copper protein, plastocyanin, has been refined using synchrotron X-ray data recorded at 173 K. The accuracy and precision of the structure are deduced from a comparison between two independent refinements based on the same set of low-temperature data.

Differences in anionic inhibition of human carbonic anhydrase I revealed from the structures of iodide and gold cyanide inhibitor complexes

Structures of human carbonic anhydrase I complexed to two anionic inhibitors have been refined at 2 Å resolution and reveal differences in the binding in the active site leading to an understanding of the mode of inhibition of the enzyme.

A crystallographic study of haem binding to ferritin

Horse-spleen apo-ferritin, the iron-storage protein, has been crystallized with Sn-protoporphyrin. The complex belongs to the F432 space group. In the final structure, protoporphyrins free of metal are observed in special positions, on the twofold axes of the ferritin molecules.

Preliminary crystallographic analysis of glyceraldehyde 3-phosphate de­hydrogenase from the extreme thermophile Thermus aquaticus

Glyceraldehyde 3-phosphate dehydrogenase from an extreme thermophile was crystallized in a large unit cell containing two tetramers (300 kDa) in the asymmetric unit. The orientations of the two tetramers were determined using the Patterson-correlation method.

High-resolution structures of single-metal-substituted concanavalin A: the Co,Ca-protein at 1.6 Å and the Ni,Ca-protein at 2.0 Å

The 1.6 Å Co,Ca-concanavalin A structure is the highest resolution lectin structure so far reported. The Co-, Ni-, Cd- and native conconavalin A structures are compared in the context of metal-ion properties, and at the saccharide-binding site.

Crystallization of hemoglobins II and III of the symbiont-harboring clam Lucina pectinata

A preliminary X-ray diffraction study is reported of the homo-tetramers of hemoglobins II and III of the symbiont-harboring clam Lucina pectinata.

The CCP4 suite: programs for protein crystallography

The CCP4 program suite, a collection of programs that can be used for macromolecular structure determination by X-ray crystallography, is described.

Use of low-molecular-weight polyethylene glycol in the crystallization of RNA oligomers

Based on crystallization trials of 26 RNA molecules, PEG400 was found to be the most successful precipitant. Crystals were obtained of 6 RNA oligomers, a DNA-RNA hybrid, transfer RNA and a self-cleaving RNA using PEG400 as precipitant or co-precipitant.

Refined three-dimensional structure of the Fab fragment of a murine IgGl,λ antibody

The refined structure of a murine IgGl-λ, Fab fragment is used to evaluate the combining site predicted using the canonical-structure approach. A new structure is described for the LI loops of murine immunoglobulin A chains.

Crystallization and preliminary X-ray analysis of the river buffalo (Bubalus bubalis L.) BB phenotype carbonmonoxyhaemoglobin

Location of active sites of NiFe hydrogenase determined by the combination of multiple isomorphous replacement and multiwavelength anomalous-diffraction methods

Four active centers (three iron-sulfur clusters and one Ni atom) are approximately lined up at a distance of ca 13 Å, which seems reasonable if they are connected with the electron-transfer chain.

Crystallization of human methylamine-treated complement C3 and C3b

Human methylamine-treated complement C3 and C3b have been crystallized using ammonium sulfate as precipitant. Maximum diffraction observed is 7.7 Å at cryogenic temperatures using synchrotron radiation.

Crystallization and preliminary X-ray diffraction studies of bacterial ribosomal protein L14

Crystals and preliminary X-ray diffraction data of ribosomal protein Ll4 from B. stearothermophilus have been obtained. It is proposed that the structure of L 14 will verify that this protein belongs to a family of structurally related RNA-binding proteins.