2. The likely regular conformations of protein molecules were proposed before they were actually observed! 2.1 This was accomplished by building precise molecular models 2.1.1 Experimental data(from X-ray studies) were closely adhered, interpreted. 2.1.2 Single bonds other than the peptide bond in the backbone chain are free to rotate2. The likely regular conformations of protein molecules were proposed before they were actually observed! 2.1 This was accomplished by building precise molecular models. 2.1.1 Experimental data (from X-ray studies) were closely adhered, interpreted. 2.1.2 Single bonds other than the peptide bond in the backbone chain are free to rotate