This thesis concerns different areas of biomolecular nuclearmagnetic resonance spectroscopy (NMR). In the first part of thethesis a new formalism for simulations of NMR pulse sequencesis introduced. The formalism is derived both from classicalmechanics and quantum mechanics and is presented forhomonuclear and heteronuclear spin systems. The formalism hasalso been adapted to systems in chemical exchange. Simulationsof pulse sequences should be more straightforward using the newformalism. In the second part of the thesis the NMR solution structuresof two ribosomal proteins are described. The ribosome isresponsible for protein production in all living cells and tounderstand the mechanism of the ribosome it is important toknow the three dimensional structure. In this thesis thestructures of S16 and S19, two of the proteins in the smallribosomal subunit, are presented. S16 is a mixed α /βprotein with a five-stranded parallel-antiparallel β-sheetand two α -helices. S19 is s mixed α/β proteinwith a three-stranded parallel-antiparallel β -sheet, oneα -helix and a short 310-helix. In the third part of the thesis a program for semiautomaticassignment of NMR-spectra is presented. Assigning resonances inthe NMR spectrum is a labor-intensive process, which can takelong time. In semiautomatic assignment a computer program aidsthe user in finding assignments but leaves all decisions to theuser, thus speeding up the process. The program described inthis thesis is a new version of ANSIG, called Ansig forWindows. The program runs on PCs under Windows and has severaltools for semiautomatic assignment. <b>Keywords:</b>nuclear magnetic resonance, structuredetermination, ribosomal proteins, NMR simulations, NMR theory,NMR assignment software, semiautomatic assignment

<p>This thesis concerns different areas of biomolecular nuclearmagnetic resonance spectroscopy (NMR). In the first part of thethesis a new formalism for simulations of NMR pulse sequencesis introduced. The formalism is derived both from classicalmechanics and quantum mechanics and is presented forhomonuclear and heteronuclear spin systems. The formalism hasalso been adapted to systems in chemical exchange. Simulationsof pulse sequences should be more straightforward using the newformalism.</p><p>In the second part of the thesis the NMR solution structuresof two ribosomal proteins are described. The ribosome isresponsible for protein production in all living cells and tounderstand the mechanism of the ribosome it is important toknow the three dimensional structure. In this thesis thestructures of S16 and S19, two of the proteins in the smallribosomal subunit, are presented. S16 is a mixed α /βprotein with a five-stranded parallel-antiparallel β-sheetand two α -helices. S19 is s mixed α/β proteinwith a three-stranded parallel-antiparallel β -sheet, oneα -helix and a short 3₁₀-helix.</p><p>In the third part of the thesis a program for semiautomaticassignment of NMR-spectra is presented. Assigning resonances inthe NMR spectrum is a labor-intensive process, which can takelong time. In semiautomatic assignment a computer program aidsthe user in finding assignments but leaves all decisions to theuser, thus speeding up the process. The program described inthis thesis is a new version of ANSIG, called Ansig forWindows. The program runs on PCs under Windows and has severaltools for semiautomatic assignment.</p><p><b>Keywords:</b>nuclear magnetic resonance, structuredetermination, ribosomal proteins, NMR simulations, NMR theory,NMR assignment software, semiautomatic assignment</p>