Introduction to selected articles from the 15th ICCBM

Selected papers from ICCBM15 have been published in the July 2015 issue of Acta Crystallographica Section F, Structural Biology Communications.

Trace fluorescent labeling for protein crystallization

The presence of a covalently bound fluorescent probe at a concentration of <0.5% does not affect the outcome of macromolecule crystallization screening experiments. Additionally, the fluorescence can be used to determine new, not immediately apparent, lead crystallization conditions.

Do protein crystals nucleate within dense liquid clusters?

The evolution of protein-rich clusters and nucleating crystals were characterized by dynamic light scattering (DLS), confocal depolarized dynamic light scattering (cDDLS) and depolarized oblique illumination dark-field microscopy. Newly nucleated crystals within protein-rich clusters were detected directly. These observations indicate that the protein-rich clusters are locations for crystal nucleation.

Towards time-resolved serial crystallography in a microfluidic device

An X-ray compatible microfluidic crystallization platform enables in situ time-resolved serial Laue crystallography.

The MORPHEUS II protein crystallization screen

MORPHEUS II is a 96-condition initial crystallization screen formulated de novo. The screen incorporates reagents selected from the Protein Data Bank to yield crystals that are not observed in traditional conditions. In addition, the formulation facilitates the optimization and cryoprotection of crystals.

Use of dynamic light scattering and small-angle X-ray scattering to characterize new surfactants in solution conditions for membrane-protein crystallization

The influence of fluorinated segment length on surfactant micelle form factors, intermicellar interaction parameters and the surfactant phase diagram in solution conditions for membrane-protein crystallization is reported.

Crystallographic analysis of a novel aldo-keto reductase from Thermotoga maritima in complex with NADP⁺

The novel thermostable aldo-keto reductase Tm1743 from T. maritima was overexpressed with an N-terminal His₆ tag, purified and co-crystallized with NADP⁺. Degradation of the N-terminal vector-derived amino acids was identified by Western blot and mass-spectrometric analyses.

Batch crystallization of rhodopsin for structural dynamics using an X-ray free-electron laser

A new batch preparation method is presented for high-density micrometre-sized crystals of the G protein-coupled receptor rhodopsin for use in time-resolved serial femtosecond crystallography at an X-ray free-electron laser using a liquid jet.

Fusion-protein-assisted protein crystallization

This review describes the two main applications of fusion proteins in protein crystallization: the `heterologous fusion-protein approach' and the `fusion of interacting proteins approach'.

Crystallographic analysis of the Arabidopsis thaliana BAG5–calmodulin protein complex

A. thaliana BAG5 (AtBAG5) and calmodulin were expressed and purified separately and then co-crystallized. The preliminary X-ray diffraction studies of the protein complex are reported. Structure determination will ultimately provide insights into the mode of interaction between AtBAG5 and calmodulin.

Structural characterization of the principal mRNA-export factor Mex67–Mtr2 from Chaetomium thermophilum

The crystal structures of the individual domains of the Mex67–Mtr2 complex from C. thermophilum have been determined and their arrangement in solution has been studied by SAXS.

Expression, purification, crystallization and crystallographic study of the Aspergillus terreus aromatic prenyltransferase AtaPT

A novel aromatic prenyltransferase from A. terreus, named AtaPT, was found to prenylate diverse novel aromatic compounds. The expression and crystallization of AtaPT are reported here.

Structure of human saposin A at lysosomal pH

A 1.8 Å resolution structure of the sphingolipid activator protein saposin A has been determined at pH 4.8, the physiologically relevant lysosomal pH for hydrolase enzyme activation and lipid-transfer activity.

Synthesis, purification and crystallographic studies of the C-terminal sterol carrier protein type 2 (SCP-2) domain of human hydroxysteroid de­hydrogenase-like protein 2

The C-terminal sterol carrier protein type 2 (SCP-2) domain of human hydroxysteroid dehydrogenase-like protein 2 (including residues Lys318–Arg416) was produced in E. coli, purified and crystallized, and X-ray diffraction data were collected to 2.10 Å resolution.

The structure of nerve growth factor in complex with lysophosphatidylinositol

The crystal structure of mouse nerve growth factor (NGF) complexed with lysophosphatidylinositol was solved and the structural determinants of NGF for LysoPI molecule recognition were identified. The influence of LysoPI in the interactions between NGF and its two receptors is modelled.

The structure of a GFP-based antibody (fluorobody) to TLH, a toxin from Vibrio parahaemolyticus

The expression, purification and crystal structure of a recombinant fluorobody to TLH are reported.

The crystal and solution structure of YdiE from Escherichia coli

YdiE, a conserved protein apparently involved in haem transport, is one of the smallest proteins produced by E. coli at only 63 residues in length. The N-terminal 20 residues of each chain in the homodimer were disordered, but crystals of the full-length protein allowed structure refinement to 1.5 Å resolution.

Expression, purification, crystallization and crystallographic study of Lutzomyia longipalpis LJL143

LJL143, a salivary protein from L. longipalpis, was produced using P. pastoris and crystallized in space group P2₁2₁2₁.