Volume 54, Issue 4, Pages 511-533 (May 2007) The Neurobiologist's Guide to Structural Biology: A Primer on Why Macromolecular Structure Matters and How to Evaluate Structural Data  Daniel L. Minor  Neuron  Volume 54, Issue 4, Pages 511-533 (May 2007) DOI: 10.1016/j.neuron.2007.04.026 Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 1 Idea to Structure Flowchart Basic steps of the process in solving a protein X-ray crystal structure are shown. Gray arrows show processes that are often iterated. (Step A) Optimization of constructs following outcome of expression tests. (Step B) Test of different expression hosts. (Step C) Crystal growth screening. (Step D) Crystal growth optimization. (Step E) Construct optimization to improve crystals. (Steps F and F1) Construct optimization to improve diffraction; (step F2), search for new crystallization or cryoprotectant conditions; (step F3) heavy atom soaks. (Step G) Production of selenomethionine-labeled protein for MAD and SAD experiments. (Step H) Building and refinement cycle for refining structure. Neuron 2007 54, 511-533DOI: (10.1016/j.neuron.2007.04.026) Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 2 Anatomy of a Protein Crystal (A) Example of an asymmetric unit (AChBP). In this case the asymmetric unit is the same as the biological unit. (B) Crystallographic symmetry operators applied to the asymmetric unit create the unit cell. Note that the AChBP pentamers in the upper right and lower left corners of the cell are in the opposite orientation of the orange pentamer. (C) Translations of the unit cell build the protein crystal lattice. Neuron 2007 54, 511-533DOI: (10.1016/j.neuron.2007.04.026) Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 3 Diffraction Experiment Schematic (A) Standard setup for data collection. The protein crystal is mounted on a goniometer (orange) and is frozen in a nylon loop. Incoming nitrogen gas at 100K maintains the frozen state of the crystal. X-rays emerge from a collimator on the X-ray source. (B) Diffracted X-rays are collected on a detector. An example of an X-ray diffraction pattern is shown with low- and high-resolution data regions indicated. In the actual setup, the detector face is normal to the X-rays. (C) Example of an initial electron density map at 2.0 Å with phases determined by selenomethionine MAD. A helix can be seen prominently on the right-hand side. (D) Final refined model. Neuron 2007 54, 511-533DOI: (10.1016/j.neuron.2007.04.026) Copyright © 2007 Elsevier Inc. Terms and Conditions

Figure 4 Example of SAXS Analysis (A) Top shows the ab initio model for SAXS data from the Kv4.3 T1 domain/KChIP1 complex calculated from the scattering data. The bottom panel shows the scattering intensity profile for the data (black) and the model (red). (B) Comparison of the crystal structure of the Kv4.3 T1 domain/KChIP1 complex with the ab initio model shows excellent correlation with the data in contrast to an alternative square-shaped arrangement shown in (C). The Dmax values show the maximal dimension of the particles calculated from the data (A) and from the models (B and C). Data are from Pioletti et al. (2006). Neuron 2007 54, 511-533DOI: (10.1016/j.neuron.2007.04.026) Copyright © 2007 Elsevier Inc. Terms and Conditions