Bernal and Hodgkin took the first X-ray photograph of a protein structure—crystalline pepsin. They showed that crystals of pepsin give an X-ray diffaction pattern, beginning protein crystallography. This may also be the beginning of structural molecular biology. The paper is freely available from Nature at this link.

Hodgkin and colleagues, including biochemist Barbara Low, solved the structure of penicillin in 1945, demonstrating, contrary to scientific opinion at the time, that it contains a β-lactam ring. The discovery was originally published by Crowfoot (Hodgkin) and Rogers-Low in 1945 in a classified report (Committee for Protein Synthesis [CPS] report #508). The work was first made public in 1949.

In 1949 Hodgkin and Low published another version of their report in Florey, Chain et al, Antibiotics: A survey, vol. 2, ch. 27, "Structure of the penicillin molecule," pp. 946-951.

Hodgkin used an IBM ‘CPS’ (Card Programmed, electronic Calculator), to perform the extremely complex math/generation/interpretation of the Fourier
synthesis yielding the 3D structure. This use of a programmed electronic punched-card tabulator was a very early use of a programmed device to speed up structure factor computation in x-ray crystallography.

With Charles W. Bunn and Annette Turner-Jones.

(Thanks to Juan Weiss for this reference and its interpretation.)

The final structure of vitamin B12. With J. Pickworth, J.H. Robertson, K.N. Trueblood, R.J. Prosen, J. G. White.  

In 1964 Hodgkin was awarded the Nobel Prize in Chemistry "for her determinations by X-ray techniques of the structures of important biochemical substances."

See also No. 12635.