Updated project metadata. In this experiment, we used advanced proteomics techniques to discern differences in energy allocation between three strains of ammonia oxidizing bacteria: Nitrosomonas europaea, Nitrosomonas ureae, and Nitrosospira multiformis, during ammonia starved and ammonia replete conditions. Replicate cultures in late log phase from the three strains were starved of ammonia for 24 hours and compared to replicate control cultures grown for the same period. All three species were grown with three biological replicates for each condition and species with the exception of two replicates from the N. ureae starved cultures due to sample processing loss. This study has, to our knowledge, produced the first complete proteomes of Nitrosospira multiformis and Nitrosomonas ureae.