The RGD motif is exposed and flexible in common with other known integrin ligands. Although CAV9 resembles coxsackie B viruses (CBVs), several substitutions in the areas implicated in CBV receptor attachment suggest it may recognise a different receptor. The structure along the fivefold axis provides new information on the uncoating mechanism of enteroviruses. CAV9 might bind a larger natural pocket factor than other picornaviruses, an observation of particular relevance to the design of new antiviral compounds.

Thyroid peroxidase (TPO) catalyzes the production of thyroid hormones and is a major autoantigen in autoimmune thyroid disease (AITD). It is believed that the majority of TPO autoantibodies bind to an immunodominant region consisting of two overlapping domains. Precise location of these domains would help our understanding of the interaction between TPO and TPO autoantibodies. 4F5 is a mouse monoclonal antibody (IgG1, kappa) that reacts with high affinity (2.6 x 10(10) mol/L(-1)) with one of the major autoantigenic regions on TPO. Heavy chain genes of 4F5 were from the VH1 germline gene family, germline genes for the D region could not be assigned and the J region was from the JH2 germline. Light chain genes were from Vkappa4/5 and Jkappa2, germline gene families. The Fab fragment of 4F5 was prepared by papain digestion, purified, crystallized, and the structure solved to 1.9 A using molecular replacement. The refined structure had an R factor of 19.5% and a free R factor of 23.9%. Deduced amino acid sequence and amino acid sequence obtained from diffraction analysis were compared and used to finalize the 4F5 Fab model. Structural analysis indicated that the structure of 4F5 is that of a standard Fab and its combining site is flat and is rich in tyrosine residues. Comparison of the structure of 4F5 with that of a TPO autoantibody Fab, TR1.9 suggests that the two antibodies are unlikely to recognise the same structures on TPO.

Human thyroid peroxidase (TPO), the key enzyme in thyroid hormone synthesis, can be produced in active form in the High Five insect cell line and when purified from the cell culture medium is soluble at concentrations of up to 18 mg/ml. This contrasts to a recent report in which human TPO produced in insect cells was found to be insoluble at high concentrations. Our concentrated TPO grows trigonal trapezohedral crystals of up to 0.5 mm in length in a vapour diffusion apparatus using polyethelene glycol as a precipitant. The crystals diffract X-rays to 6 Å resolution and the diffraction data from the crystals have been analysed giving unit cell dimensions. A potential molecular replacement solution has been identified using myeloperoxidase (MPO) as a phasing model.

Crystals have been grown of 2‐keto‐3‐deoxygluconate aldolase (KDG aldolase) from the hyperthermophilic archaeon Sulfolobus solfataricus that diffract to 2.2 Å resolution. The enzyme catalyses the reversible aldol cleavage of 2‐keto‐3‐dexoygluconate to pyruvate and glyceraldehyde, the third step of a modified non‐phosphorylated Entner–Doudoroff pathway of glucose oxidation. S. solfataricus grows optimally at 353 K and the enzyme itself has a half‐life of 2.5 h at 373 K. Knowledge of the crystal structure of KDG aldolase will further understanding of the basis of protein hyperthermostability and create a target for site‐directed mutagenesis of active‐site residues, with the aim of altering substrate specificity. Three crystal forms have been obtained: orthorhombic crystals of space group P212121, which diffract to beyond 2.15 Å, monoclinic crystals of space group C2, which diffract to 2.2 Å, and cubic crystals of space group P4232, which diffract to 3.4 Å.