Crystal structure determination of 4-zinc bovine insulin at 1.9 A resolution

With the isomorphous difference Fourier method and the restrained least-squares refinement technique, the crystal structure of 4-zinc bovine insulin in space group R3 was determined. The final crystallographic residual is 0.19 at 1.9 A resolution. Based on the refined model, the structural mechanism for prolonged action of 4-zinc insulin is discussed.