Structural 3D visualization of a bacteriophage T4 capsid. This ribbon view molecular model was visualized with UCSF ChimeraX software. Secondary structures are colour-coded: red for alpha helices, yellow for B-strands and green for loops. T4 is a bacteriophage that infects Escherichia coli bacteria. The capsid forms the head of the bacteriophage and stores the genetic material. Phages such as T4 are a possible therapy against multi-drug-resistant bacteria.