ACORN2: new developments of the ACORN concept

ACORN2, an improved, more effective version of ACORN, is described and its performance is illustrated by application to a number of known structures, starting with phases from either very small fragments, physical methods or molecular replacement. When the starting fragment is centrosymmetric and gives no definition of an enantiomorph, ACORN2 refinement resolves the problem and converges to a possible solution.

A neutron crystallographic analysis of phosphate-free ribonuclease A at 1.7 Å resolution

A neutron crystallographic analysis of phosphate-free RNase A has been carried out at 1.7 Å resolution.

Structure of the restriction–modification controller protein C.Esp1396I

The crystal structure of the free restriction–modification controller protein C.Esp1396I is reported.

Rotational order–disorder structure of fluorescent protein FP480

An analysis of the rotational order–disorder structure of fluorescent protein FP480 is presented.

Cyclic olefin homopolymer-based microfluidics for protein crystallization and in situ X-ray diffraction

A cyclic olefin homopolymer-based microfluidics system has been established for protein crystallization and in situ X-ray diffraction.

Averaged kick maps: less noise, more signal…and probably less bias

Averaged kick maps are the sum of a series of individual kick maps, where each map is calculated from atomic coordinates modified by random shifts. These maps offer the possibility of an improved and less model-biased map interpretation.

Structure of Hordeum vulgare NADPH-dependent thioredoxin reductase 2. Unwinding the reaction mechanism

The first crystal structure of a cereal NTR, a protein involved in seed development and germination, has been determined. The structure is in a conformation that excludes NADPH binding and indicates that a domain reorientation facilitated by Trx binding precedes NADPH binding in the reaction mechanism.

Structure of the apo decarbamylated form of 2,3-diketo-5-methylthio­pentyl-1-phosphate enolase from Bacillus subtilis

The crystal structure of the apo decarbamylated form of 2,3-diketo-5-methylthiopentyl-1-phosphate enolase has been solved at 2.3 Å resolution.

Polarizable atomic multipole X-ray refinement: application to peptide crystals

A method to accelerate the computation of structure factors from an electron density described by anisotropic and aspherical atomic form factors via fast Fourier transformation is described for the first time.

Application of general formulas for the correction of a lattice-translocation defect in crystals of a lentiviral integrase in complex with LEDGF

Corrections for lattice-translocation defects (LTDs) remove the intensity modulation introduced by LTD and decompose the composite structure that is statistically averaged from two LTD-related structures into the original unscrambled structure.

Structure of the single-stranded DNA-binding protein from Streptomyces coelicolor

The first crystal structure of a single-stranded DNA-binding protein from a member of the genus Streptomyces has been solved and refined at 2.1 Å resolution. It shows variations in quaternary structure that have previously only been found in mycobacterial SSBs.

Analysis of lattice-translocation disorder in the layered hexagonal structure of carboxysome shell protein CsoS1C

A hexagonal layered structure leads to lattice-translocation disorder in crystals of a carboxysome shell protein. Approaches are described for handling translocation problems. In addition, a rare situation is uncovered in which the rotational symmetry in intensity data and in Patterson maps exceeds the rotational symmetry of the crystal itself.

Structure and epimerase activity of anthocyanidin reductase from Vitis vinifera

Recombinant grape anthocyanidin reductase synthesizes the naturally rare flavan-3-ol epimers with 2S configuration. Its 2.2 Å resolution crystal structure explains the inactivity of the enzyme in the presence of high salt concentrations.

Automatic implementation of precise grid screens: the four-corners method

An efficient and accurate method has been developed for the preparation of the customized crystallization grid screens employed in protein crystallizations.

To scavenge or not to scavenge: that is the question

Analysis of a series of diffraction data sets measured from several native as well as nicotinic acid-soaked crystals of trypsin suggests that this potential scavenger does not have any statistically significant effect on the amount of radiation damage incurred in the crystals on X-ray irradiation at 100 K.

Comment on Microfibrillar structure of type I collagen in situ by Orgel et al. (2006), Proc. Natl Acad. Sci. USA, 103, 9001–9005

Comment on Microfibrillar structure of type I collagen in situ by Orgel et al. (2006), Proc. Natl Acad. Sci. USA, 103, 9001–9005.

On the packing structure of collagen: response to Okuyama et al.'s comment on Microfibrillar structure of type I collagen in situ

A response to the comment on Microfibrillar structure of type I collagen in situ [Okuyama et al. (2009), Acta Cryst. D65, 1007–1008].

Protein Crystallography – A Concise Guide