Crystals on the cover 2014

The Editors highlight the crystals featured on the cover and a new series of articles.

Introduction to protein crystallization

The gateway to X-ray crystallography is the growth of macromolecular crystals. An attempt is made here to acquaint investigators with the principles and practice of protein crystallization, some recent innovations, and to touch upon some of the remaining problems.

Structural mechanism of DNA recognition by the p202 HINa domain: insights into the inhibition of Aim2-mediated inflammatory signalling

Structural and biochemical data demonstrate that p202 recognizes foreign DNA in a distinct manner compared with AIM2/Aim2, leading to a new model for the negative regulation of Aim2-mediated inflammasome activation by p202.

The structure of endo­thiapepsin complexed with a Phe-Tyr reduced-bond inhibitor at 1.35 Å resolution

An oligopeptide containing a reduced analogue of a Phe-Tyr dipeptide was found to have good inhibition activity against endothiapepsin, and the crystal structure of the inhibitor–enzyme complex has been determined at 1.35 Å resolution.

Structures of adenosine kinase from Trypanosoma brucei brucei

The structures of T. brucei brucei adenosine kinase in open and closed conformations give insight into the substrate-binding mode and can be used to improve the properties of antitrypanosomal agents.

Structure of Mycobacterium tuberculosis nucleoside diphosphate kinase R80N mutant in complex with citrate

The crystal structure of the R80N mutant of nucleoside diphosphate kinase from M. tuberculosis has been determined at 1.9 Å resolution. Biochemical data and structural analysis provide important information on the stability of the hexamer. A citrate is bound in the catalytic site where the nucleotide phosphate groups are usually located.

Crystallization and preliminary X-ray analysis of a complex of the FOXO1 and Ets1 DNA-binding domains and DNA

The DNA-binding domains of Ets1 and FOXO1 were expressed, purified, and crystallized in complex with DNA containing a composite sequence for a noncanonical forkhead binding site and an ETS site. Diffraction data were collected to a resolution of 2.2 Å.

Purification, crystallization and preliminary X-ray diffraction analysis of a novel keto-de­oxy-D-galactarate (KDG) dehydratase from Agrobacterium tumefaciens

The expression, purification, crystallization and preliminary X-ray diffraction analysis of a novel keto-deoxy-D-galactarate dehydratase from A. tumefaciens are described.

Expression, purification, crystallization and preliminary X-ray diffraction studies of phosphoglycerate mutase from Staphylococcus aureus NCTC8325

The cloning, overexpression, purification, crystallization and preliminary X-ray crystallographic analysis of phosphoglycerate mutase from S. aureus NCTC8325 are reported.

Cloning, purification, crystallization and preliminary X-ray studies of HMO2 from Saccharomyces cerevisiae

The expression, purification, crystallization and preliminary crystallographic analysis of the high-mobility group protein (HMO2) from S. cerevisiae are reported.

Crystallization and preliminary X-ray study of Vibrio cholerae uridine phosphorylase in complex with 6-methyluracil

The crystallization and preliminary X-ray study of a complex of uridine phosphorylase from V. cholerae with 6-methyluracil are reported.

Purification, crystallization and preliminary X-ray analysis of an HA17–HA70 (HA2–HA3) complex from Clostridium botulinum type C progenitor toxin

The crystallization and preliminary X-ray characterization of an HA17–HA20 complex from C. botulinum type C toxin are reported.

Purification, crystallization and preliminary X-ray diffraction of the N-terminal calmodulin-like domain of the human mitochondrial ATP-Mg/P_i carrier SCaMC1

The N-terminal calmodulin-like domain of the human mitochondrial ATP-Mg/P_i carrier SCaMC1 was crystallized in the presence of Ca²⁺. X-ray diffraction data were collected to 2.9 Å resolution from crystals which belonged to space group P6₂22.

Crystallization and preliminary X-ray diffraction studies of a surface mutant of the middle domain of PB2 from human influenza A (H1N1) virus

A double mutation (P453H and I471T) improved the solubility of the middle domain of PB2 from influenza A virus and the shape of the crystals that were obtained. A small crystal was used to test the diffraction and a preliminary X-ray diffraction data set was collected to 2.30 Å resolution.

Crystallization and preliminary X-ray crystallographic analysis of the small subunit of the heterodimeric laccase POXA3b from Pleurotus ostreatus

Crystals of the small subunit of POXA3b, a heterodimeric laccase (multicopper oxidase) from P. ostreatus, belonged to space group P4₁2₁2 or P4₃2₁2 and contained two molecules in the asymmetric unit related by a noncrystallographic twofold axis. X-ray data were collected to a maximum resolution of 2.5 Å using a synchrotron source.

Cloning, expression, purification and preliminary X-ray crystallographic analysis of mouse protein arginine methyltransferase 7

The structure of mouse protein arginine methyltransferase 7 was solved by the SAD method. The protein was crystallized in two different crystal forms.

Expression, purification, crystallization and preliminary X-ray diffraction analysis of the novel modular DNA-binding protein BurrH in its apo form and in complex with its target DNA

The DNA-binding protein BurrH from B. rhizoxinica has been expressed, purified and crystallized in its apo form and in complex with its target DNA. Preliminary X-ray diffraction analysis is reported.

Expression, crystallization and preliminary X-ray diffraction analysis of thioredoxin gluta­thione reductase from Schistosoma japonicum in complex with FAD

The preparation and crystallographic study of S. japonicum thioredoxin glutathione reductase are reported.

Cloning, overexpression, purification and preliminary X-ray analysis of a feast/famine regulatory protein (Rv2779c) from Mycobacterium tuberculosis H37Rv

A feast/famine regulatory protein (Rv2779c) from M. tuberculosis H37Rv was cloned, overexpressed, purified and crystallized. The crystals diffracted to a resolution of 2.8 Å and belonged to space group P2₁2₁2.

Crystallization and preliminary X-ray diffraction analysis of FabG from Yersinia pestis

β-Ketoacyl-(acyl carrier protein) reductase (FabG), an enzyme from Y. pestis involved in fatty-acid synthesis, was crystallized and X-ray diffraction data were collected to 2.3 Å resolution.

Preliminary X-ray diffraction analysis of thermostable β-1,4-xylanase from Streptomyces sp. S9

Recombinant XynAS9, a thermophilic GH10 xylanase from Streptomyces sp. S9, was crystallized and X-ray diffraction data were collected to 2.08 Å resolution.

Crystallization and preliminary X-ray crystallographic analysis of L-arabinose isomerase from thermophilic Geobacillus kaustophilus

L-Arabinose isomerase from G. kaustophilus was overexpressed, purified and crystallized, and a preliminary X-ray diffraction data set was obtained.

Purification, crystallization and preliminary X-ray crystallographic analysis of a rice Rac/Rop GTPase, OsRac1

OsRac1, a small GTPase from O. sativa, was expressed, purified and crystallized. An X-ray diffraction data set was collected from a native crystal to 1.9 Å resolution.

Crystallization and structure determination of a symmetrical `football' complex of the mammalian mitochondrial Hsp60–Hsp10 chaperonins

Mammalian mitochondrial Hsp60 and Hsp10 chaperonins were expressed, purified and co-crystallized. The structure of their symmetrical complex was determined by molecular replacement.

Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of recombinant human fumarase

Recombinant human fumarase has been overexpressed in E. coli and crystallized in the presence of polyethylene glycol as a precipitant agent. The structure was solved by molecular-replacement techniques.

Purification, crystallization and preliminary X-ray analysis of the inverse F-BAR domain of the human srGAP2 protein

Despite possessing an N-terminal F-BAR domain, the srGAP2 protein regulates neurite outgrowth and neuronal migration by causing membrane protrusions reminiscent of the activity of I-BAR domain proteins. In this study, the F-BAR domain of human srGAP2 was crystallized and diffracted to 3.50 Å resolution.

Measurement of the intrinsic variability within protein crystals: implications for sample-evaluation and data-collection strategies

The intrinsic variability between and within macromolecular crystals has a large effect on screening and data-collection strategies. Measures of this variability and their implications for data collection are presented.