Contrary to the well studied RNA polymerases of gram negative bacteria, RNA polymerase of Bacillus subtilis, a gram positive bacterium, contains two additional subunits, referred to as delta and omega1. A well-structured N-terminal domain of subunit delta has been overexpressed in an E. coli expression system, labeled with stable isotopes C-13 and N-15, and investigated by nuclear magnetic resonance. A standard set of triple resonance NMR experiments was measured and almost all resonances of the protein backbone were assigned. Resonance frequencies of the side-chains were assigned using 3D TOCSY- and NOESY-type spectra. Three-bond coupling constant J(HNHA) were obtained from 3D HNHA experiments. Chemical shifts of backbone nuclei, medium range NOEs, and the three-bond coupling constants were analyzed and secondary structure was predicted. Internuclear distance restraints were extracted from NOESY spectra and used in structure calculation.