Structure of CspA (PDB entry 4bl4). (a) Stereoscopic views of the 4bl4 main chain shown in cartoon representation with and without the 2Fo − Fc electron-density map contoured at 1.5σ. Colouring runs from the N-terminus (blue) to the C-terminus (red). (b) Cylinder representation of the CspA subunit with helices numbered from the N-terminus. This figure was generated using PyMOL (Schrödinger LLC).